Anatomy chapter 20 immune system

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Summarize the role of TC Cells (from the notes):

1) Activated TC cell binds to its target cell. 2) Protein called perforin is released and perforates the target cell's plasma membrane 3) TC cell then releases enzymes that enter the target cell's cytosol and catalyze reactions that degrade target cell nucleus, leading to fragmentation of the target cell's DNA and its death. TC cells can also induce the process of programmed cell death (apoptosis), or programmed cell death. 4) TC cell detaches from target cell and looks for another one

Type I hypersensitivity response (from book):

1) An allergen binds to a B cell 2) The B cell differentiates into plasma cells that secrete IgE antibodies, which bind to a mast cell sensitizing it 3) The allergen binds to the sensitized mast cell, and IgE molecules on the cell form cross-links that cause the cell to release inflammatory mediators from its granules, triggering an inflammatory response

The Big Picture of the Immune Response to a Bacterial Infection:

1) Bacteria damage cells and induce an inflammatory response, as local macrophages ingest the bacteria 2) Neutrophils enter the area in large number and phagocytize bacteria 3) In lymphatic tissue, dendritic cells activate TH cells, and B cells bind bacterial antigens and are activated by TH cells 4) B cells differentiate into plasma cells that secrete antibodies to agglutinate bacteria 5) TH cells secrete cytokines that enhance phagocyte and B cell activity

T Cell Activation, Clonal Selection, and Differentiation. Summarize the process by which T cells are activated:

1) Dendritic cells display the antigen fragments on their MHC molecules, and the MHC-antigen complex binds to the receptor of a specific naïve TH or TC cell clone triggering T cell activation known as clonal selection 2)TH or TC binds a co-stimulator (CD-4 for TH or CD-8 for Tc) and becomes activated 3)Activated TH or Tc cell clones proliferates and differentiates into effector cells (those that cause immediate effects) and memory T cells (responsible for cell-mediated immunological memory)

State the 3 Steps of Naïve B Cell Maturation:

1) Hematopoietic Stem cells from the Lymphoid line divide in the bone marrow 2) B cells mature in the bone marrow where self-reactive B cells are destroyed 3) Mature Naïve B cells leave the bone marrow and travel to lymphoid organs

List everything about neutrophils (from notes)

1) Most numerous granulocyte; phagocytes that ingest pathogens and kill with chemicals such as hydrogen peroxide, hypochlorous acid, and lysozyme -Bacterial pathogens -Damage plasma membranes of pathogens -Reside in blood and are recruited

State the 4 Steps of B cell activation, clonal selection and differentiation (from notes):

1) Naïve B cell binds its' antigen to its' B cell receptor and becomes activated. 2) Sensitized B cell processes the antigen and presents it on its class MHC class II molecules. 3) The B cell then binds to a helper T cell to become fully activated. 4) B cells differentiate into (1) Plasma cells , which secrete antibodies; and (2) memory B cells , which are long-lived cells that do not secrete antibodies but will respond to antigens upon a second exposure

The basic effects of secreted antibodies are:

1) agglutination and precipitation 2) opsonization 3) neutralization 4) complement activation 5) stimulation of inflammation

When tumor cells are discovered via immune surveillance, they are eliminated by the following process: (the big picture of the immune response to cancer cells)

1) cancer cells damage surrounding cells and induce an inflammatory response 2) NK cells migrate to the area and begin to destroy the cancer cells and secrete interferons 3) Dendritic cells ingest cellular debris and migrate to lymph nodes, where they activate naive TH and Tc cells 4) Activated TH cells secrete cytokines that stimulate effector Tc cells to kill cancer cells

there are three main series of enzymatic reactions, or pathways, by which complement proteins may be activated:

1) classical pathway 2) the lectin pathway 3) the alternative pathway

When a virus does gain entry, the response proceeds by the following steps: (immune response to the common cold)

1) infected cells trigger an inflammatory response and secrete interferons 2) Interferons prevent infection in neighboring cells and activate natural killer (NK) cells, which lyse infected cells 3) Dendritic cells activate TH and Tc cells in lymphatic tissue, and cytokines from TH cells activate B cells bound to viral particles 4) B cells differentiate into plasma cells, which secrete antibodies that bind and neutralize the virus 5) TH cells secrete cytokines that amplify the immune response, and Tc cells destroy virally infected cells

the basic immune response in three different scenarios:

1) infection with the common cold virus 2) infection with a strain of toxin-producing bacteria 3) a cancerous tumor

The stages proceed as follows:

1) local macrophages are activated 2) neutrophils migrate by chemotaxis to the damaged tissue and phagocytize bacteria and cellular debris 3) Monocytes migrate to the tissue by chemotaxis and become macrophages, which phagocytize pathogens and cellular debris 4) The bone marrow increases production of leukocytes, leading to leukocytosis

Many situations could lead to development of autoimmunity Some of these situations include the following:

1) release of self antigens not previously encountered by T cells 2) Foreign antigens mimic self antigens 3) Cells may inappropriately express class II MHC molecules 4) Certain pathogens nonspecifically activated B cells

State the 4 Steps of B cell activation, clonal selection and differentiation (from book):

1) the B cell clone binds its antigen and is activated 2) The sensitized B cell processes the antigen and presents it on its class II MHC molecules. It then binds to a TH cell, which secretes cytokines that activates the B cell 3) The B cell divides repeatedly; the resulting cells differentiate into plasma cells and memory cells 4) Plasma cells secrete antibodies

Function of TC cells (from book):

1) the activated Tc cell binds to its target cell 2) The Tc cell releases perforin, which forms pores in the target cell's plasma membrane 3) The Tc cell then releases enzymes that can now enter the target cell and fragment its DNA 4) When the target cell begins to degrade, the Tc cell detaches and searches for a new target cell

What are the three steps of the inflammatory response, part 1: effects of inflammatory mediators (from the picture)

1) tissue damage occurs 2) Damaged cells and mast cells release inflammatory mediators 3) Inflammatory mediators trigger: vasodilation of arterioles, increased capillary permeability, occurrence of pain, recruitment of other cells: chemotaxis

MHC molecules in essence serve as ------- for specific components of antigens that are then displayed to naïve T cells

"docking sites"

Chemotaxis=

"movement"

The thymus does what

"screens" these cells and mediates the destruction of those clones that cannot recognize antigens

This bacterium causes a variety of infections, the most common of which is streptococcal pharyngitis; commonly called

"strep throat"

Local macrophages are activated (in the notes)

("first responders") are activated within minutes of cellular injury; phagocytize pathogens and damaged cells; contain invading pathogens

There are two basic stages to the inflammatory response:

(1) Damaged cells release inflammatory mediators that cause local changes in the damaged tissue; and (2) phagocytes arrive at the area and clean up the damaged tissue

This reaction occurs in three situations:

(1) Foreign antigens bind to normal self antigens; (2) donor erythrocytes infused into an individual are mismatched in the ABO/Rh antigen groups; and (3) self-reactive B cells are not destroyed in the bone marrow, which leads to autoimmunity

An endogenous antigen, however, is one of two things:

(1) a foreign antigen present on a pathogen that lives inside your cell, such as an intracellular bacterium, or (2) a foreign or self antigen encoded by your DNA

Innate immunity consists of two main components:

(1) a group of antimicrobial proteins, including the antimicrobial complement proteins and a variety of cytokines; and (2) several types of cells, including neutrophils, macrophages, and NK cells

Each of these chains has two types of regions:

(1) constant (C) regions, which are relatively similar among antibodies and are responsible for many of the antibodies' effects; and (2) variable (V) regions, which are unique sequences of amino acids responsible for antigen recognition and binding

Three most common antigen presenting cells:

(macrophages, dendritic cells, and B lymphocytes)

Other classes of anti-allergy medications and treatments include the following:

-Antileukotriene: block the enzyme that produces leukotrienes, which inhibits many aspects of the allergic inflammatory response -Corticosteroids: block the synthesis of leukotrienes and prostaglandins and are potent inhibitors of allergic inflammation. They are commonly used for related allergic disorders such as asthma -Allergen immunotherapy: commonly known as "allergy shots," involves administration of the allergen in increasing doses, with the aim of inducing tolerance to the allergen and a diminished IgE response

What does a fever do (in the notes)

-Fevers denature bacteria's proteins that are enzymes so they can't carry their normal metabolism and either stop growing or die. Fever also shortens the time the immune system takes to respond because the leukocytes become more active -increase activity of leukocytes and denature enzymes in invading bacteria

There are several key differences between the two responses:

-First, the secondary immune response has a shorter lag phase (about 1-3 days), and its antibody levels peak more rapidly (3-5 days) and reach a peak 100-1000 times larger -Also, the main antibody involved in the secondary response is IgG, thanks to the fact that many of the memory B cells have already undergone class switching, whereas it's IgM in the primary response. -In addition, the secondary response lasts longer than the primary response. -Finally, the antibodies secreted in the secondary immune response are more effective

Increased capillary permeability (in the notes):

-Increased capillary permeability: increase "leakiness" of local capillary beds -Allows protein-rich fluid to leak from blood vessels into tissue spaces; leads to cardinal sign of swelling -Proteins in fluid include clotting proteins such as fibrinogen, complement proteins, and proteins needed for tissue repair

Name anti-inflammatory medications:

-Nonsteroidal anti-inflammatories (NSAIDs) ibuprofen -Corticosteroids mimic cortisol's anti-inflammatory effects; prednisone (give to auto-immune conditions because they have inflammatory problems; asthma) -Nasprin -Naproxen -Anti-leukotriene

Vasodilation (in the notes):

-Vasodilation: occurs due to histamine and bradykinin -Relax smooth in arterioles; allows blood to flow to injured tissues, and area becomes congested with blood (hyperemia) -Accounts for redness and heat accompanying inflammation as blood is warmer than surface body temperature

The four basic kinds of tissue and organ transplants, also known as grafts, are as follows:

-autografts -isografts -allografts -xenografts

Basophils are located primarily in the -----, although a related type of cell called the mast cell is located in --------

-blood -mucous membranes

Occurrence of pain (in the notes)

-bradykinin and prostaglandins, trigger action potentials in peripheral process of sensory neurons (at there end are going to be nociceptors at free nerve endings), which lead to pain; serves numerous protective functions -Lets us know when our tissues are being damaged to avoid further damage -Causes a temporary loss of function; both of which allows body to begin to repair damage

Class I MHC molecules present ------ antigens, whereas class II MHC molecules present -----antigens

-endogenous, or those synthesized inside cell -exogenous, or those cell takes in by phagocytosis

Macrophages: Neutrophils: Monocytes:

-first responders -second responders -third responders

It's easy to think of exogenous as meaning "------" and endogenous as meaning "---," but don't forget that endogenous antigens can be -------

-foreign -self -foreign or self

C3b also binds to-----—clusters of antigens bound to antibodies— and triggers their ------

-immune complexes -phagocytosis

Interferons are generally produced in response to ---------------, and are named for their capacity to

-infection with intracellular agents such as viruses or intracellular bacteria -"interfere" with the ability of the pathogens to infect other cells

Some of the main functions of activated effector TH cells include the following:

-innate immunity: stimulation of macrophages -Adaptive cell-mediated immunity:activation of Tc cells -Adaptive antibody-mediated immunity: stimulation of B cells

A vaccine may be any of several types, depending on its components, which can include the following:

-live, attenuated vaccines -Inactivated (killed) vaccines -subunit vaccines

However, their phagocytic functions appear to be less critical than those of -----, and they are primarily involved in responses to -------

-neutrophils -parasitic pathogens

List everything about interleukins (from notes)

-produced by leukocytes; -stimulate production of neutrophils by bone marrow, stimulate NK cells, trigger production of interferons, and activate T cells (stimulate leukopoiesis-white blood cells)

List everything for Interferons (from notes)

-produced by macrophages, dendritic cells, NK cells, and cells of adaptive immunity in response to infection with intracellular viruses or bacteria; -inhibits viral replication inside host cells

List everything about tumor necrosis factor (from notes):

-secreted by macrophages in response to bacteria and other pathogens; -attracts phagocytes to infection, -increases phagocytes activity and -stimulates phagocytes to release more cytokines

and they are due to the following actions of inflammatory mediators:

-vasodilation of arterioles -Increased capillary permeability -occurrence of pain -recruitment of other cells: chemotaxis

2. Activated complement proteins

trigger the release of inflammatory mediators from cells such as basophils and mast cells, and act as inflammatory mediators themselves

Several complement proteins, particularly C5a and C3a, enhance this response by

triggering basophils and mast cells to release chemicals that mediate inflammation

This is why you feel cold, or have "chills," when you have a fever—the hypothalamus is

triggering responses to elevate body temperature to the new, higher range

Stimulation of inflammation:

IgE binds mast cells and basophils, and triggers release of inflammatory mediators

his first exposure generates a primary immune response, which occurs slowly and produces few symptoms, but does result in the formation of large numbers of

IgE molecules that coat mast cells and basophils

---- antibodies are also opsonins able to coat pathogens and bind and activate phagocytes, which greatly enhances phagocytosis

IgG

Opsonization:

IgG coats antigens and binds phagocytes, enhancing phagocytosis

Most neutralizing antibodies are of either the

IgG or the IgA class

This gives us the types --------which you can remember with the mnemonic GAMED

IgG, IgA, IgM, IgE, and IgD

Several antibodies, particularly -------, bind and activate the complement proteins of innate immunity

IgM and IgG

Immune surveillance is absolutely critical to the prevention of

tumor development

The basic subunit of an antibody, is a Y-shaped protein formed from four peptide chains,

two heavy (H) and two light (L) chains

This appears to be the case with -------, in which the immune system destroys the insulin-producing cells of the pancreas

type 1 diabetes mellitus

The most common type of hypersensitivity disorder is

type I, or immediate, hypersensitivity

A decrease in the function of one or more components of the immune system results in an

Immunodeficiency disorder

Memory T cells are responsible for cell-mediated --------, in which these cells respond more quickly and efficiently to subsequent exposures to an antigen

Immunological memory

The phenomenon whereby cells of adaptive immunity respond more quickly and efficiently to subsequent exposures to an antigen.

Immunological memory

Antigenic determinant:

unique portion of antigen to which receptor binds

A -------, also known as an immunization, involves exposing an individual to an antigen to elicit a primary immune response and generate memory cells

vaccination

The cytokines known as interferons, abbreviated IFN, are produced by a

variety of cells, including macrophages, dendritic cells, NK cells, and cells of adaptive immunity

These substances trigger the

vasodilation and increased capillary permeability of an inflammatory response

The nonphagocytic cells include

NK cells and basophils

Passive immunity may be

Naturally acquired through passage from mother to fetus, and in breast milk or Artificially acquired through injection of antibodies to toxins or venoms

Neutrophils migrate by chemotaxis to the damaged tissue and phagocytize bacteria and cellular debris (in the notes)

Neutrophils migrate by chemotaxis, margination and diapedesis; neutrophil migrate (chemotaxis) to damaged tissue and phagocytize bacteria and cellular debris attracted by inflammatory mediators and activated complement proteins allow them to adhere to capillary wall (process called margiantion); increased capillary permaeability provides space between endothelial cells for neutrophils to squeeze through into damaged tissue (known as diapedesis)

What do anti-inflammatory medications do

Reduce inflammation and pain by blocking enzymes needed for production of prostaglandins and leukotrienes

Subsequent exposures to the allergen in a sensitized person result in rapid responses that occur within a few minutes. This happens because

when the allergen binds the sensitized mast cell or basophil, the IgE molecules on the cell form cross-links

Alternative pathway—

which begins at the cleavage of an inactive complement protein called C3 into its active form C3b; begins when inactive complement proteins encounter foreign cells such as bacteria or may happen spontaneously

membrane attack complex, or MAC does what

which inserts itself into the plasma membrane of the target cell, creating a pore that causes it to lyse

We can divide the arrival and activation of phagocytes into stages, based on

which phagocytes enter the area and the processes occurring there

In this second scenario, we examine the immune response to the bacterium

Streptococcus pyogenes

It then presents the antigen to a particular ------, which is specific for its individual MHC-antigen complex

T cell clone

Every distinct T cell has a receptor on its surface, called (appropriately enough) the -------- that binds a specific antigen

T cell receptor

The immune system is quite effective at eliminating cancers before they ever get the chance to damage other tissues. This effectiveness is largely due to certain cells of the immune system, especially

T cells and NK cells, that "scan" the cells in the body for tumor antigens, a function known as immune surveillance

For poorly understood reasons, other cell types may also inappropriately express class II MHC molecules. This activates

T cells and triggers an immune response to these normal self antigens

Type IV: Delayed-Type Hypersensitivity mediated by (from notes)

T cells rather than antibodies. TH cells recognize antigens bound to MHC molecules and activate macrophages and TC cells. Poison ivy and oak; tuberculin skin test

Other viruses are able to block display of viral antigens on class I MHC molecules, which prohibits

TC cell activation

Note that the immune response to this bacterium did not involve

TC cells

Adaptive antibody-mediated immunity: stimulation of B cells:

TH cells directly bind to B cells and stimulate them to proliferate and differentiate. They also secrete various interleukins that stimulate B cell proliferation and increase antibody production

Adaptive cell-mediated immunity: activation of TC cells

TH cells secrete the cytokine interleukin-2 (IL-2), which is required to activate TC cells

Innate immunity: stimulation of macrophages

TH cells secrete the cytokine interleukin-3 (IL-3), which stimulates macrophages to become more efficient phagocytes. It also causes macrophages to produce interleukin-12, which stimulates TH cells to generate more IL-3 in a positive Feedback Loop

pus:

The accumulation of dead leukocytes, dead tissue cells, and fluid leads to a whitish mixture

What good, then, does a fever do us?

The best current hypothesis is that our phagocytes function more efficiently at a slightly higher body temperature, which helps to increase the rate of recovery from whatever caused the inflammation

Inflammatory mediators trigger several effects, which you have almost certainly seen first-hand on occasion (shown in step ❸❸):

The injured area becomes red and swollen, feels warm to the touch, and hurts

there is one key difference between this response and a normal response:

The plasma cells secrete IgE instead of IgG or IgM

Inflammatory mediators attract and activate

a number of leukocytes, particularly macrophages and neutrophils

immunocompetent:

able to mount a normal response to foreign antigens

This protective mechanism prevents

abnormal TC cell activation

Secondary immunodeficiencies—

acquired through infection, trauma, cancer, or certain medications

Many of the inflammatory mediators, particularly bradykinin and prostaglandins, trigger ----------------

action potentials in the peripheral processes of sensory neurons

Antibodies, also known as immunoglobulins or gamma globulins, are the "action" component of antibody-mediated immunity, in that they are directly responsible for its

actions or effects in mediating the destruction of antigens to which they bind

This allows complement to ---- and ----- the foreign cell with its membrane attack complex

activate lyse

Indeed, in the absence of TH cells and IL-2, most TC cells fail to

activate and become unresponsive to the antigen

Many of these effects represent an integration of adaptive and innate immunity—the antibodies of adaptive immunity often -------

activate phagocytes and complement proteins of innate immunity

However, if an individual comes into contact with these pathogens, co-stimulatory signals

activate these T cells, which then attack self cells

Naïve T cells must bind their specific antigens before they become

activated

T cells respond to these antigens by becoming

activated

TNF is secreted primarily by

activated macrophages in response to certain bacteria and other pathogens

3) Cells may inappropriately express class II MHC molecules (from notes)

activates T cells that destroy self antigens in Type I diabetes mellitus

In addition, they secrete an antimicrobial cytokine that ----------

activates macrophages and enhances phagocytosis

There are two types of antibody-mediated immunity:

active and passive

Bacteria also have ways of evading the immune response, including

adaptations that allow them to attach more strongly to host cells, secretion of substances that destroy antibodies, and inhibition of phagocytosis

note that complement and cytokines have roles in -------, as well

adaptive immunity

The clumping of cells is known as

agglutination

This type of hypersensitivity is more commonly known as

allergies, and the disorders that accompany it are called allergic disorders

These drugs are able to bind to erythrocytes in certain patients, which

alters their antigens and causes them to be recognized as foreign

Immediate hypersensitivity reactions occur when an individual reacts to a foreign antigen,

an allergen

involves a systemic release of histamine and other inflammatory mediators

anaphylactic shock

Conditions such as heat stroke, certain brain diseases, and reactions to medications can cause fevers, and these fevers will not reduce with administration of

anti-inflammatory medications

What reduce fever

anti-pyretics (not inflammation)

Active immunity-make

antibodies

Passive immunity-receive

antibodies

antibody-mediated immunity involves B cells and proteins secreted by B cells, called

antibodies

Neutralization:

antibodies bind pathogenic components of toxins and block toxic effects

Agglutination and precipitation:

antibodies clump antigens together to enhance phagocytosis

This form of immunity lasts only the amount of time that the ------- which is about 3 months on average

antibodies stay in the bloodstream,

In fact, we'll see that the structure of a B cell receptor is almost identical to that of an

antibody

The second phase begins when the

antibody level in the blood rises dramatically

We now look to the second arm of adaptive immunity:

antibody-mediated immunity, also called humoral immunity

The memory B cells are responsible for

antibody-mediated immunological memory

Like memory T cells, the memory B cells respond more efficiently when the

antigen is encountered a second time

An antibody has V regions at the tips of the two arms of the protein, so the basic subunit of an antibody has two -------, one on each arm

antigen-binding sites

Like macrophages, these cells function as

antigen-presenting cells

In addition, they can function as --------, cells that display portions of the pathogens (antigens) they ingest on their plasma membranes

antigen-presenting cells (APCs)

The unique portion of the antigen to which the receptor binds is known as its

antigenic determinant

The two classes of molecules also differ in the types of ----- they display

antigens

Self Antigens:

antigens present on your own cells (glycoprotein)

However, both allografts and xenografts do contain

antigens that the organ recipient's immune system recognizes as foreign

Given the enormous number of people who suffer from allergic disorders, the market for medications that treat allergies is huge. Most medications available over the counter are -------, or medications that block cells' receptors for histamine

antihistamines

In addition to cells, the innate immune response is mediated by a variety of plasma --------, including complement proteins and several types of cytokines

antimicrobial proteins

Fevers may be alleviated, or made to "break," either spontaneously or through the action of certain medications. Medications that reduce an inflammation-mediated fever are known as

antipyretics

T cell receptor:

are found on surface of every T cell; receptor must bind a specific antigen before cell can become activated

Indeed, many anti-inflammatory medications such as ----- and ----- are also antipyretics

aspirin ibuprofen

Effects of TNF include inducing the flu-like symptoms we just described:

attracting phagocytes to the area of infection, increasing the activity of phagocytes, and stimulating phagocytes to release additional cytokines

This produces an

autoimmune disorder

This prevents the development of -------, in which B cells recognize self antigens as foreign and produce ------ that bind self antigens

autoimmunity autoantibodies

relatively rare cell that is generally nonphagocytic is the

basophil

Classical pathway—

begins when inactive complement proteins bind to antibodies bound to antigen

Note that as this is occurring, complement proteins are also ------

being activated

lack the ability to metastasize and do not divide indefinitely and are not considered cancerous

benign tumors

The actions of antibodies are based on their ability to ------, which leads to multiple effects on pathogens

bind antigens

This action, known as opsonization, makes phagocytes do what

bind more strongly to the pathogen and enhances phagocytosis

IgG antibodies, produced in higher amounts in the secondary immune response,

bind more tightly to and have a higher affinity for their antigens

In type II hypersensitivity, also known as antibody-mediated hypersensitivity, the antibodies produced by the immune response that

bind to foreign antigens also bind to self antigens

Another function of C3b and the components of the membrane attack complex is

binding to certain viruses and neutralizing them, or blocking them from infecting host cells

IgE:

binds parasitic worm antigens and allergens to basophils and mast cells, and stimulates them to release granules (degranulation) with histamine and heparin (allergic reactions)

This is mediated by C5b, which

binds to the surface of a pathogen and provides a docking site for several other activated complement proteins

Prostaglandins and leukotrienes are important targets for medications that

block the inflammatory response

Neutrophils generally reside in the ----- and must be recruited to ------ by chemical signals

blood damaged tissues

Fever is defined simply as a

body temperature above the normal range, which is generally between 36 and 38° C (or 97 and 99° F)

B cells develop in the ------from the lymphoid cell line, where billions of B cells are produced each day

bone marrow

T cells are formed in the-----, but they leave the bone marrow and migrate to the ---- to mature

bone marrow thymus

The complement system play a critical role in

both innate and adaptive immunity

In addition, they activate various components of

both innate and adaptive immunity, such as stimulating nearby cells to produce antimicrobial proteins

Our final scenario involves a disease that is responsible for over 8 million deaths per year worldwide:

cancer

These complexes deposit in various places in the body, including the

capillary beds in the kidneys, blood vessel walls, the synovial membrane of joints, and the choroid plexus in the brain

When antigens enter the body, they are ----- in these lymphoid organs

captured

2.) Foreign antigens mimic self antigens (from notes)

cardiac cell antigens resemble Strep in rheumatic fever

These four signs—redness, heat, swelling (or edema), and pain—are known as the

cardinal signs of inflammation

Given the importance of the immune system, it is probably no surprise that disorders of this system can result in

catastrophic homeostatic imbalances

The first arm of the adaptive immune system is

cell-mediated immunity

These cells respond primarily to

cells infected with intracellular pathogens (viruses and intracellular bacteria), cancer cells, and foreign cells such as those from a transplanted organ

Naïve T:

cells remain that have not yet encountered their specific antigens

Macrophages are activated by a variety of stimuli, including

certain substances present on pathogens, chemicals secreted by damaged cells, and signals from the cells of adaptive immunity

Basophils are granulocytes whose granules contain

chemicals that mediate inflammation (inflammatory mediators)

Like regular basophils, mast cells contain granules with

chemicals that trigger inflammation, particularly that involved in allergic responses

Naïve cytotoxic T (TC) cells generally interact only with

class I MHC molecules

naïve helpe​​r T (TH) cells generally interact with

class II MHC molecules

The elevated numbers of leukocytes allow the damaged area to be

cleared and any pathogens removed so that cells such as fibroblasts can begin the process of healing

Each population of T cells that can respond to a specific antigen is known as a

clone

The proteins in the fluid include

clotting proteins such as fibrinogen, complement proteins, and proteins needed for tissue repair

Antibodies can bind to antigens on more than one cell. This creates a ----- of cells that are cross-linked by their attachment to antibodies

clump

One reason for this efficiency is that memory T cells have no need of a ------, which makes the response considerably more rapid

co-stimulator

Normally, T cells specific for these antigens do not attack self cells because of the lack of

co-stimulatory signals

Antibodies also trigger inflammation indirectly through their activation of ----

complement

Activated B cells secrete antibodies that lead to

complement activation and complement-mediated lysis of erythrocytes

Opsonization involves proteins such as

complement coating the pathogen and activating phagocytes

Complement system—

consists of 30 plasma proteins produced primarily by liver; play a critical role in both innate and adaptive immunity

Though few in number, these "first responders," the only phagocytes present within the first hour or so of the inflammatory response, perform the critical function of

containing invading pathogens

When a person is infected with a parasite, eosinophils do what

cover it and release the contents of their granules

Many pathogens can induce the production of

cytokines that nonspecifically activate B cells, resulting in the production of autoantibodies

NK cells are also -----, releasing substances that destroy their target cells

cytotoxic

Macrophages also have -------, meaning that they can secrete these substances onto pathogens that are too large to ingest

cytotoxic effects

The chemicals from the granules do what

damage the parasite and either destroy it or make it easier for other immune cells to destroy

Inflammation begins when a cell is ------ by anything, including trauma, bacterial or viral invasion, toxins, heat, or chemicals

damaged

This triggers a series of events that together act to wall off the

damaged area from the rest of the body, clean up damaged cells and cell components, and bring cells and proteins to the area to repair the damaged tissue

after tissue damage occurs (such as that caused by the splinter in step ❶❶), the inflammatory response begins when the

damaged cells and nearby mast cells release inflammatory mediators

After several minutes, neutrophils from the blood migrate to the

damaged tissue

Cancer cells are formerly normal body cells that have undergone mutations causing them to

de-differentiate (become less specialized), lose control of their cell cycles, and lose their attachments to the surrounding cells and extracellular matrix

Both conditions make you feel hot, although your body temperature is actually ------

decreasing

The process of T cell activation begins with a

dendritic cell processing and displaying antigen fragments on its MHC molecules

The final group of phagocytic cells is the

dendritic cells

Once the neutrophils are in the tissue, they then begin to

destroy bacteria and other cellular debris

T cells are generally exposed to self antigens during development, and those self-reactive T cells are

destroyed

This is largely because B cell cl​ones ​that recognize self antigens (self-reactive B cells) are

destroyed

Neutrophils can ingest many types of cells, but are particularly effective at

destroying bacterial pathogens

Some complement proteins are able to lyse, or "pop," the plasma membranes of pathogens, leading to their ------

destruction

TC cell __________ from target cell and looks for another one

detaches

Their ability to interact with class I MHC molecules means they can

detect abnormalities in any cell type with a nucleus, which is critical for the detection of cancer cells, foreign cells, and cells infected with intracellular pathogens such as viruses and bacteria

This is a process known as

diapedesis

However, if the B cells are not exposed to their specific antigens within a few days to a few weeks, the cells -----

die

Eventually, all of the neutrophils and many of the macrophages

die themselves

TH and TC cells have very --------, although they do interact and depend on each other to function properly

different roles

The neutrophils and macrophages in the damaged tissue go to work

digesting pathogens and damaged cells

TH or TC cells increase in number when activated and differentiate into -----, or those that cause the immediate effects, and -----

effector cells memory T cells

In the damaged tissue, monocytes

enlarge and mature into macrophages, which ingest pathogens and damaged cells with the neutrophils

The inflammatory mediators also increase capillary permeability, which provides

enough spaces between endothelial cells for neutrophils to squeeze through into the damaged tissue

TC cell then releases _________ that enter the target cell's cytosol and catalyze reactions that degrade target cell nucleus, leading to fragmentation of the target cell's DNA and its death. TC cells can also induce the process of --------, or programmed cell death.

enzymes apoptosis

Such microorganisms are especially pathogenic and difficult for the immune system to

eradicate

Note, however, that they are not present on the surface of -------, which is why blood is considerably easier to donate than other organs and tissues

erythrocytes

Although the immune response works most of the time in preventing serious homeostatic disruptions, certain pathogens have evolved ways to ----- elements of the innate and/or adaptive immune responses

evade

Instead, TH cells primarily

exert their effects through the secretion of cytokines that then activate and enhance various components of the immune response

For example, the agranulocytes known as monocytes do what

exit bloodstream and take up residence in various tissues where they develop into macrophages

The next group of cells to be attracted to the area by chemotaxis is the circulating monocytes, which

exit the blood in the same way as neutrophils

Antigens may be classified as

exogenous or endogenous

When several antibodies bind a single cell, their complement-binding sites are

exposed

innate immunity is present in the body without needing

exposure to a specific antigen

The length of time during which active immunity lasts depends on several factors, particularly the

extent of exposure

For this reason, failure of TH cells to function, which we see with conditions such as acquired immunodeficiency syndrome (AIDS), can lead to

failure of the entire immune response

an individual with a fever is referred to as

febrile

One of the most recognizable, and unpleasant, signs of illness is

fever

Interestingly, many cytokines induce "flu-like" symptoms, including

fever, chills, and aches (the aches are due to stimulation of inflammation)

IgM:

first type secreted when B-cell is activated; RBC Ab's anti-A and anti-B are this type, so agglutination can occur; can activate complement proteins. (largest of all the antibodies and has the most antigen binding sites) (agglutination and precipitation)

Many cytokines induce "--------" symptoms; including fever, chills, and body aches

flu-like

Type II: Antibody-Mediated Hypersensitivity occurs when (from notes)

foreign antigens bind to self-antigens; transfusion reactions; penicillin allergy; self-reactive B cells not destroyed leads to autoimmunity

There are ---- types of hypersensitivity disorder (numbered I-IV) that are classified according to the exact immune components causing the hypersensitivity

four

Dendritic cells—(from notes)

function as antigen-presenting cell; present to T cells and some B cells and activate them

Secondary Immune Response:

future exposure to same antigen activates memory B cells formed during the primary immune response; antibodies secreted now are more effective as they bind more tightly and have a higher affinity for their antigens

Inactivated (killed) vaccines

generally require several repeat vaccinations, known as "boosters." (weak primary immune response)

The name "antigen" comes from the phrase "antibody generating," a reference to their ability to

generate the production of antibodies from B cells

Primary immunodeficiencies—

genetic or developmental in nature

As T cells mature, they undergo gene rearrangements that lead to a huge variety of

genetically distinct T cells

Basophils—(from notes)

granules contain chemicals that are inflammatory mediators such as histamine and heparin; involved in allergic responses

Some very small antigens, called -----, are immunogenic only if they are attached to a protein carrier

haptens

The cancer cells invade and destroy ------ as they crowd out normal cells and compete for nutrients

healthy tissues

In this way, they "-----" immune response, hence their common name

help

cell-mediated immunity involves the different classes of T cells, including the

helper T (TH) cells, also known as CD4 cells, and the cytotoxic T (TC) cells, also known as CD8 cells

The common cold is due to a variety of viruses that typically have a -------, which is why researchers have yet to develop a vaccine for the pathogens

high mutation rate

commonly referred to as a "-----------."

high white cell count

Pyrogens cause the hypothalamic thermostat to reset to a

higher range

Inflammatory mediators such as ------ and ------ are potent vasodilators

histamine bradykinin

These links cause the cell to release the inflammatory mediators in its granules, including

histamine, leukotrienes, and prostaglandins

These mediators can include

histamine, serotonin, cytokines, a peptide called bradykinin, and a group of related lipids known as prostaglandins and leukotrienes

This allows them to create chemicals such as

hydrogen peroxide, hypochlorous acid, and hydroxide anions, which kill ingested pathogens

Pyrogens act on the -----, the small component of the diencephalon (the central core of the brain) that regulates the homeostasis of many regulated physiological variables

hypothalamus

Regardless of what makes the fever break, it results from the

hypothalamus being reset back to the normal temperature range

Type III: Immune Complex-Mediated Hypersensitivity mediated by (from notes)

immune complexes or clusters of soluble antigens bound to antibodies; deposit in organs

Normally, several processes ensure immune self tolerance—that the

immune system does not react to self antigens and damage the body's own tissues and cells

This ensures that an individual is -----, or able to mount a normal response to foreign antigens

immunocompetent

Only certain antigens generate a response from the immune system. Those with this capability are called

immunogens "immune generating"

Each antibody is named with the two-letter abbreviation "Ig," which stands for "-------," followed by a letter that designates its ------

immunoglobulin class

Involves B cells and proteins secreted by B cells, called antibodies also called _________________ or _________________. B cells have B cell receptors that bind to specific ___________, and a group of B cells that bind to a specific antigen is known as a ----- . The antibodies secreted by a B cell _____ bind to the same antigen as the B cell receptor

immunoglobulins gamma globulins antigens clone clone

immunosuppression

impaired ability to provide an immune response

IgA:

in glandular secretions like mucous, tears, saliva; functions in agglutination and neutralization (found in secretions like saliva and milk in oral cavity protecting you from invading organisms)

Complement proteins circulate primarily in their

inactive forms and must be activated by a complex cascade of events mediated by enzymes

In severe infections, the amount of TNF secreted can ------ dramatically

increase

Activated T cells in turn secrete substances that

increase the activity of the macrophages, in an example of a positive feedback loop

Cytokines produced by the activated phagocytes act on cells in the bone marrow to

increase the production of neutrophils and monocytes over the next 3-4 days

This results in

increased blood flow to the damaged tissue, and the area becomes congested with blood, a condition known as hyperemia (hyper- = "above" or "elevated," -emia = "blood")

Act on hypothalamus and raises set point so body responds by

increasing body temperature by increasing muscle activity such as shivering

The cytokine known as tumor necrosis factor, or TNF, is named for the fact that it was originally discovered through its ability to

induce necrosis (death) of tumor cells

This is evidenced by the fact that fevers may be seen in the absence of any

infectious pathogens following severe trauma, burns, or even childbirth

Although we tend to associate fevers with infection, remember that fever is a nonspecific response and can tell you only that widespread ------ is present

inflammation

It is also important to remember that occasionally fevers are not related to

inflammation

From a clinical perspective, fever is a critical warning sign of ------ processes occurring somewhere in the body

inflammatory

tissue damage initiates inflammatory response as damaged cells and local mast cells release ---------

inflammatory mediators

In addition, certain activated complement proteins trigger the release of

inflammatory mediators from cells such as basophils and mast cells, and act to a limited degree as inflammatory mediators themselves

Recruitment of other cells (in the notes)

inflammatory mediators recruit leukocytes to damages tissue (chemotaxis) particularly macrophages (first responders) and neutrophils (second responders) while complement proteins are simultaneously being activated

When they deposit in these organs and tissues, they initiate an

inflammatory reaction that attracts neutrophils and causes damage to the affected areas

Like all innate responses, the series of events known collectively as the -------- occurs in reaction to any cellular injury

inflammatory response

It is common to associate pus with infection; however, pus indicates only that an

inflammatory response took place

One of their primary actions is to

inhibit viral replication inside host cells

Most antipyretics work in the same manner as anti-inflammatories, by

inhibiting the formation of prostaglandins

The antibody IgE directly triggers inflammation by

initiating the release of inflammatory mediators from mast cells and basophils

This is one of many instances of ----- and ------ immunity working together

innate adaptive

Primary Immunodeficiency Disorders may impair either

innate or adaptive immunity

Like inflammation, fever is an ------ to cellular injury

innate response

TH cells are required for normal function of all components of the immune system, including

innate, antibody-mediated, and cell-mediated immunity

Full T cell activation requires the

interaction of the naïve T cell with other molecules on the cells, called co-stimulators

For example, many viruses block or inhibit cytokines such as

interferons

Isografts—

involve organs and tissues transplanted between two genetically identical individuals; like autografts these result in no response from Tc cells because antigens bound to class I MHC molecules are not recognized as foreign (uncommon)

Autografts—

involve tissue transplanted form one site to another in same individual; skin grafts; no response from Tc cells because antigens bound to class I MHC molecules are not recognized as foreign

vaccination:

involves exposing an individual to an antigen to elicit a primary immune response and generate memory cells

Lectin pathway—

is initiated when proteins called lectins bind to carbohydrates on the surface of microbes

However, an intracellular bacterium, or one that lives inside its host cell, causes a response that involves TC cells because

its antigens are displayed on class I MHC molecules

The primary function of cytotoxic T cells is evident from their name—they

kill other cells, specifically those with foreign antigens bound to class I MHC molecules

Inflammatory mediators increase the permeability, or "------," of local capillary beds

leakiness

The structure of most capillaries prevents them from

leaking all of their contents to the interstitial fluid

The final response occurs in the bone marrow, where

leukocytes are produced

This leads to an elevated number of circulating leukocytes, a condition called

leukocytosis

However, monocytes live ------ and are more ----- than neutrophils

longer aggressive

This causes the hypothalamus to sense the febrile temperature as being too high, and it triggers negative feedback mechanisms to

lower the body's temperature

Naïve B cell clones that complete maturation enter the circulation and eventually take up residence in

lymphoid organs such as the spleen and lymph nodes

The phagocytic cells include

macrophages, neutrophils, eosinophils, and dendritic cells

The name comes from the fact that MHC molecules are

major determinants of compatibility among tissue and organ donors and recipients

T cells cannot directly interact with an antigen. Instead, they can interact only with pieces of antigen bound to glycoproteins, called

major histocompatibility complex (MHC) molecules

These mutations result in a mass of unspecialized cells called a ------, whose cells are capable of indefinite growth and can -----, or spread, through the lymphatic system or blood to other parts of the body

malignant tumor metastasize

how this works: The inflammatory mediators make the capillary endothelium in the damaged area "sticky," and the neutrophils adhere to the capillary wall, a process called

margination

Live, attenuated vaccines:

meaning that their ability to cause disease has been greatly reduced (weakened) -varicella (strong primary immune response)

Together these complement proteins form a structure collectively known as the

membrane attack complex, or MAC

It results in the production of

memory cells and large numbers of antibodies and is, therefore, relatively long-lasting, ranging from years to a lifetime

The granulocytes known as eosinophils are phagocytes that can

migrate from the blood to the tissues where they are needed

There are ----- of different clones in the immune system, but only a few cells of each clone exist in the ----- at any give​n time

millions body

Then if the individual is exposed to the antigen a second time, a secondary immune response will occur and symptoms will be

minimal

Within ----- of a cellular injury, macrophages already present in the tissue enlarge and begin to ---------

minutes phagocytize pathogens and damaged cells

Type I: Immediate Hypersensitivity: (from the notes)

most common type known allergies; First exposure to an allergen: the allergen binds a B cell which triggers B cell differentiation into plasma cells that secrete IgE antibodies. Subsequent exposures to identical allergens in a sensitized individual result in a rapid response that occurs within a few minutes. Local reactions, such as those in the nasal cavity, produce the common symptoms of runny nose and itchy eyes; urticaria (hives); asthma; anaphylactic shock;

Allografts—

most common type of grafts; involve organs and tissues transplanted between two nonidentical individuals of same species (most common is the kidney)

Each of these situations also relies on

multiple genetic factors that increase an individual's tendency to develop autoimmunity

One of the biggest challenges to effective vaccination is posed by pathogens that have a high rate of ------:random changes in their genetic makeup

mutation

1) Release of self antigens not previously encountered by T cells (from notes)

myelin sheath: blood brain barrier and multiple sclerosis

The first group of nonphagocytic cells we'll cover is the

natural killer (NK)

MHC molecules are found on

nearly nucleated cells

A rejected organ or tissue first fails to function properly, and then its cells die as TC cells destroy them, a condition known as

necrosis

Bacterial toxins, viral proteins, and animal venoms are molecules with specific components that are harmful. Antibodies bind to these components, as well as certain viruses and bacteria, and prevent them from interacting with our cells. This renders the toxin inactive, which is known as

neutralization

The most predominant granulocyte is the

neutrophil

Inflammatory mediators and activated complement proteins attract

neutrophils and enable them to leave the blood and enter the tissue

Passive immunity results in

no memory cells formed and no lasting protection

The inflammatory response is a

nonspecific response to cellular injury

NK cells (natural killer cells) cytotoxic: (from notes)

nonspecifically kill cancerous cells and cells infected with viruses; secrete antimicrobial cytokine that activates macrophages and enhances phagocytosis

Certain viral and bacterial antigens closely resemble

normal self antigens

These cells, which are known as naïve T cells because they have

not yet encountered their specific antigens, eventually reside in the blood, lymphoid organs, or other lymphatic tissue

Autoimmune disorders may be localized and affect only ---- organ or tissue, or they may be systemic and affect ----parts of the body

one multiple

The complement protein C3b acts as an -----, binding both pathogens and phagocytes

opsonin

An exogenous antigen is one that

originates outside the cell and must be taken into the cell by phagocytosis

Although one tends to blame the pathogen for these symptoms, usually it is your ---------- that actually causes them

own immune response

When neutrophils are activated, their

oxygen consumption increases, a phenomenon called the respiratory burst

This leads to the extremely important and underappreciated effect of ------, which serves numerous protective functions

pain

IgD :

participates in antigen recognition and the activation process (B cell receptors)

is found when preformed antibodies are passed from one organism to another

passive immunity

Macrophages kill

pathogens they have ingested with chemicals, including hydrogen peroxide and hypochlorous acid (the active component in bleach)

An example of the first situation is the reaction to antibiotic medications such as

penicillin

These other substances must usually be coupled with a ----- to function fully as an antigen

peptide

Antigens are usually-----, but they may also be substances such as carbohydrates, lipids, and metals (nickel is a notoriously antigenic metal)

peptides

Protein called ________ is released and _________ the target cell's ------

perforin perforates plasma membrane

The third and final phase of antibody-mediated immunity is the

persistence of a population of B cells called memory B cells that react much more rapidly and efficiently if the antigen is encountered again

Certain granulocytes and agranulocytes can function as

phagocytes

Immune complexes are generally cleared by ------, but certain complexes are difficult for macrophages to ingest

phagocytes

Like macrophages, neutrophils are highly effective

phagocytes

The second component of the inflammatory response deals with the

phagocytes that ingest pathogens and cellular debris

We can divide the cells of innate immunity into two types

phagocytic cells and nonphagocytic cells

Unlike most other immune cells, helper T cells have no

phagocytic or cytotoxic abilities

the process by which cells ingest particles and other cells, called

phagocytosis

activated B cells divide into two populations:

plasma cells and memory B cells

Common allergens include

pollen, dust mites, pet dander, peanuts, shellfish, and bee venom

Clone:

population of T cells that respond to a specific antigen; millions of different clones in immune system, but only a few cells of each clone exist in body at any given time

However, sometimes these processes fail, and the result is

populations of self-reactive T cells or of B cells that secrete antibodies that bind to self antigens, called autoantibodies

Note that both processes end up with the same result:

portions of antigens displayed on the plasma membrane attached to MHC molecules. These MHC-antigen complexes then interact with and activate T cells

Similar to agglutination is the process called ------, which involves soluble antigens (proteins and other biological molecules) instead of whole cells

precipitation

This function is evident from the name, as opsonin means "--------"

prepare for eating

The substances they ingest are

presented to T cells (and, to a lesser extent, B cells), which are then activated

This clears these complexes from the circulation, which is critical to

preventing them from lodging in different tissues around the body

There are two basic types of immunodeficiency disorders:

primary immunodeficiencies, which are genetic or developmental in nature, and secondary immunodeficiencies, which are acquired through infection, trauma, cancer, or certain medications

AIDS Helper T cells are ------- Helper T cells are central to -------- Most patients die from "-------"

primary target both antibody and cell-mediated responses opportunistic infections

4) Certain pathogens nonspecifically activate B cells (from notes)

produce cytokines SLE (systemic lupus erythematosus)

The name "interleukin" means "between leukocytes," which reflects the fact that they are

produced by leukocytes and many of their actions affect other leukocytes

Interferons are actually partly responsible for

producing some of the symptoms associated with flu-like illnesses, including muscle aches and fever

IL-2 also stimulates the

proliferation of TC cells

T cell receptors normally have low affinity for their MHC-antigen complexes, which is a

protective mechanism that prevents unnecessary naïve T cell activation

This allows

protein-rich fluid to leak from the blood vessels into the tissue spaces, and leads to the cardinal sign of swelling

cytokines are:

proteins produced by several types of immune cells that enhance the immune response in some way

A wound filled with pus is said to be

purulent

Indeed, certain bacterial species, known as ------, are known for producing quite purulent wounds

pyogenic bacteria

Fever is initiated when chemicals called ------ ; pyro- = "fire," -gen = "causing") are released from damaged cells or certain bacteria

pyrogens

For this reason, innate immunity is typically

quick to respond to a pathogen, generally within seconds to a few hours

During this time, neutrophils stored in the bone marrow are released into the blood, which leads to a

rapid, acute rise in the level of circulating neutrophils

This leads to a

reaction from the immune system that, if left untreated, results in rejection of the organ or tissue

Active immunity may be

received naturally through exposure to an antigen via infection or artificially via a vaccination

NK cells are lymphocytes with the remarkable ability to

recognize cancerous cells and cells infected with certain viruses in spite of the fact they cannot recognize antigens

Other T cell clones, known as self-reactive T cells do what

recognize self antigens as foreign and would attack your cells if released into the circulation

When the T cell receptor ------and ------ this complex, multiple changes are triggered inside the T cell and the process of activation begins

recognizes and binds

Some T cell clones are capable of ------ and ------ to pathogens, whereas others are not

recognizing responding

The final effect of inflammatory mediators is the

recruitment of leukocytes to the damaged area through a process known as chemotaxis

injured area becomes

red and swollen, feels warm to touch, and hurts

Hyperemia accounts for the

redness and heat that accompany inflammation (because blood is warmer than the body's surface)

4 cardinal signs of inflammation

redness, heat, swelling (edema), pain

Xenografts—

relatively rare procedures that involves organs and tissues transplanted between two individuals of different species, such as a pig and a human (most common is heart valve)

T cells that do survive this screening are

released into the circulation when they mature

In some cases, it also causes a temporary loss of function—you're unlikely to run on your broken ankle when it's throbbing—which allows the body to -------

repair the damage

Activated local macrophages are generally the first cells to

respond to a cellular injury, where they ingest other cells and cellular debris

Currently, there are a number of drug therapies for HIV-1 including

reverse transcriptase and protease inhibitors and entry blockers

This occurs with the disease -------, which occurs after infection with a specific species of streptococcal bacterium whose antigens resemble those on the heart muscle

rheumatic fever

Some macrophages remain fixed in certain tissues, whereas others

roam freely in the body

They appear to do this by

scanning the cells for irregularities and by reacting to cells that have bound to antibodies (another example of innate and adaptive immunity working together)

it is not the first exposure, it is the ------

second

Antigens present on your own cells, called -----, are not immunogens in your body

self antigens

These self-reactive T cells are also destroyed, ensuring

self tolerance and preventing our T cells from attacking our own cells

Self Tolerance:

self-reactive T cells are destroyed; prevent T cells from attacking self cells

Autoimmune Disorders occur

self-reactive T cells or B cells that secrete antibodies bind to self antigens, called autoantibodies

As with type I hypersensitivity, TH cells must be ----- by an initial exposure, and the reaction occurs with subsequent exposures

sensitized

Such mast cells and basophils are said to be

sensitized

This results in the possibly fatal condition of ------, in which a marked drop in blood pressure, failure of organs such as the kidneys and liver, inappropriate blood clotting, and a severe drop in blood glucose concentration seriously disrupt homeostasis

septic shock

What are the three steps of the inflammatory response, part 1: effects of inflammatory mediators (from notes)

1. Release of inflammatory mediators 2. Activated complement proteins 3. List and describe the 4 Cardinal signs of inflammation

List everything about macrophages (from notes)

1.) First cells to respond to a cellular injury, where they ingest other cells and cellular debris 2.) Macrophages kill pathogens with chemicals, including hydrogen peroxide and hypochlorous acid (active component in bleach) Functions as 3.) Antigen-presenting cells (APCs) cells that display portion of pathogens (antigens) they ingest on their plasma membranes 4.) Activate T cells with these antigens that secrete substances that increase activity of macrophages; example of a positive feedback loop

There are several cytokines that are involved in innate immunity, including the following:

1.) Tumor necrosis factor 2.) Interferons 3.) Interleukins

1. Release of inflammatory mediators:

1.) by damaged cells and local mast cells including histamine, serotonin, cytokines, bradykinin, prostaglandins and leukotrienes

Describe the 5 effects of Activated complement proteins

1.) cell lysis by formation of a membrane attack complex (MAC) 2.) enhanced inflammation 3.) neutralization of viruses 4.) enhancing phagocytosis due to opsonization 5.) clearance of immune complexes.

List everything about Eosinophils (from notes)

1.) phagocytes that can migrate from blood to tissues where they are needed -parasitic pathogens -cover parasites and release contents of their granules -chemicals from granules damage parasite and either destroy it or make it easier for other immune cells to destroy

There are two types of MHC molecules:

1.Class I MHC molecules 2.Class II MHC molecules

They remain in the bone marrow to mature, but only about ----- of these cells finish their maturation process

10%

This includes the familiar sign of

shivering, increased muscle activity that generates heat to bring body temperature to the new set point

Antibody Structure (from notes):

2 heavy (H) and 2 light (L) chains, constant regions where complement-binding sites are found and variable regions where antigen-binding sites are located

complement system consists of around

30 plasma proteins that are produced primarily by the liver

Antibody levels peak about 7-14 days after the antigen is encountered. It is during the lag phase that you generally feel "------"

sick

For this reason, you may not feel "-----" when exposed to the same antigen or may experience only mild symptoms

sick

IgG:

80% of all Antibodies; targets viruses, bacteria; can cross placenta (anti-Rh); function in opsonization, neutralization and activates complement (most common making up 80 percent, the rest are 25 percent) (long lasting antibody u are going to produce to protect you)

Over ----- of all T cells die in the thymus in this manner

95%

Mast cells—(from notes)

similar function as basophils. Mast cells are in the tissues while basophils are in the blood. They will also secrete histamine

Primary Immune Responses:

A B cell specific for that antigen recognizes it, the activated B cell proliferates and differentiates into plasma and memory B cells, and plasma cells begin to secrete antibodies

Note that neutrophils are able to ingest only a

single microbe before they themselves also die

The primary immune response is effective, but it's -----—there is an initial 4- to 5-day lag phase as the B cells proliferate, differentiate into plasma cells and memory cells, and begin to secrete antibodies

slow

This response is much ------than that of neutrophils, because it takes several hours for monocytes to mature and there are far fewer monocytes than neutrophils stored in the bone marrow and the circulation

slower

dendritic cells are the most important ----- in the immune response

APCs

Complement activation:

Antibodies activate complement proteins, leading to cell lysis

Examples of these effects include

stimulating production of neutrophils by the bone marrow, stimulating NK cells, triggering the production of certain types of interferons from different leukocytes, and activating T cells

Although it might seem that you frequently get sick with a cold, in truth most pathogens, viruses included, are deterred by the body's ----- and so never even gain entry into the body

surface barriers

class II MHC molecules are found only on the

surfaces of antigen-presenting cells, including dendritic cells, macrophages, and B lymphocytes

The pus is generally absorbed into the ----------- when healing has completed

surrounding tissues and lymphatic vessels

These include ----- and ------------ serving the skin, which makes the skin appear red or flushed

sweating dilation of the blood vessels

When too high what happens

sweating and vasodilation occur

This is the proposed mechanism behind the disease --------, in which infection with a certain virus is followed by production of antibodies to proteins in DNA, erythrocytes, platelets, and leukocytes

systemic lupus erythematosus

Activated TC cell binds to its ------

target cell

The antibodies secreted by a B cell clone bind to the same antigen as

the B cell receptor

Autografts and isografts result in no response from TC cells because

the antigens bound to class I MHC molecules are not recognized as foreign

Subunit vaccines

the bacteria responsible for tetanus and diphtheria secrete disease-causing toxins. Vaccinations called toxoids contain inactivated toxins from these bacteria, which induce the immune system to produce antibodies to the toxins (weak primary immune response)

active immunity, so named because

the body's cells actively respond to an antigen

The hypothalamus normally functions as

the body's thermostat, and maintains body temperature within the normal range through a series of negative feedback loops

The first phase involves a

B cell clone recognizing its specific antigen, which triggers it to undergo changes and start secreting antibodies

Just as T cells have T cell receptors, B cells have ------ that bind to specific antigens, and a group of B cells that bind to a specific antigen is known as a ------

B cell receptors clone

only ---- and ------ normally display class II MHC molecules

B cells antigen-presenting cells

an antigen is a substance that

B or T cells recognize

The bone marrow increases production of leukocytes, leading to leukocytosis (from notes)

Bone marrow increases production of Leukocytes, leading to leukocytosis; bone marrow increases production of leukocytes due to cytokines produces by activated phagocytes, leading to elevated number of leukocytes in blood called leukocytosis

Pathogens that have moved past our surface barriers next meet our bodies' second line of defense:

the cells and proteins of innate immunity

Let's start with one of the most frequent infectious conditions in the world:

the common cold

There are five basic classes of antibody, which are grouped according to the structure of their

C regions

The three pathways converge when

C3b is activated, which in turn cleaves the inactive protein C5 into its active component C5b

HIV-1 preferentially binds and interacts with cells displaying

CD4 molecules so therefore _____________ T cells are affected

Disorders take three forms:

the immune system may overreact and damage tissues, which results in a hypersensitivity disorder; (2) one or more components of the immune system may fail, which is an immunodeficiency disorder; and (3) the immune system may treat self antigens as foreign and attack the body's own tissues, which is an autoimmune disorder

You have probably experienced at least one type of the group of immune system dysfunctions known as the hypersensitivity disorders, in which

the immune system's response causes tissue damage

This process is known as ----- because the antigen "selects" a particular T cell clone

Clonal selection

Autoimmunity results in a type II, III, or IV hypersensitivity reaction, which is what produces

the organ and tissue damage characteristic of the disease

Class I MHC molecules are found on

the surface of the plasma membrane on nearly all nucleated cells

This is particularly true of TC cells, because

their effects are so destructive when they are activated

Cytokines have been studied for their ------ uses in conditions such as persistent viral infections and certain cancers

therapeutic

However, some antigens are sequestered, meaning that

they are not exposed to the developing T cells

TH cells are so important to B cell activation that they derive their name from this role—

they are required to "help" initiate B cell response

What do they do?

they relax the smooth muscle in arterioles supplying the damaged tissue, causing the vessels to "open up" and blood to flow through them more freely

The antibody-mediated immune response has ---- basic phases

three

Immunocompetent:

thymus "screens" T cells and mediates destruction of those clones that cannot recognize antigens

Pain lets us know when our -----------

tissues are being damaged so that we can try to avoid further damage

major histocompatibility complex (MHC) molecules:

Glycoproteins found on the surface of cells that bind and display antigen fragments.

AIDS caused by

Human Immunodeficiency Virus 1 (HIV-1), which is spread through contact with infected blood, semen, vaginal fluid, or breast milk

At this higher range, the hypothalamus interprets normal body temperature as being -------, which triggers the negative feedback loop

too low

TC cells are activated in the same way as TH cells, with the addition that they require

IL-2 from TH cells to activate fully

Outline the 4 basic steps of how exogenous antigens are processed and displayed by Class II MHC molecules:

❶❶ The cell ingests a pathogen by phagocytosis. ❷❷ The phagocytic vesicle fuses with a lysosome; the pathogen is degraded and its antigens are fragmented. ❸❸ The lysosome fuses with a vesicle from the RER that contains class II MHC molecules, and an antigen fragment binds to the MHC molecule. ❹❹ The MHC-antigen complex is inserted into the cell's plasma membrane.

Outline the 4 basic steps of how endogenous antigens are processed and displayed on Class I MHC molecules:

❶❶ The cell synthesizes either a self antigen or a foreign antigen. ❷❷ The antigen is broken down by enzymes in the cytosol. ❸❸ An antigen fragment containing the antigenic determinant is transported into the rough endoplasmic reticulum (RER) and is coupled with a class I MHC molecule in the RER membrane. ❹❹ The MHC-antigen complex leaves the RER by a vesicle and is inserted into the cell's plasma membrane.


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