BIOL 2510 Immune System

Effects of Inflammation

- Fluid (exudate) moves from blood to injured or infected area • Fluid, protein, immune cells to eliminate pathogens, promote healing • Vasodilation brings more blood to the area and warms the area, inhibiting some pathogen growth • Contraction of vessel endothelial cells opens gaps between them, increasing capillary permeability • Loss of plasma proteins decreases capillary osmotic pressure, thus decreasing fluid reabsorption into blood • Extra fluid is taken up by lymphatic capillaries in the area ("washing") - Carries away debris and allows lymph node monitoring of its contents

Cell-mediated

Acquired Defense:The adaptive/specific defenses: Third line of defense: Two branches of adaptive immunity - _______ immunity involving T-lymphocytes

Humoral immunity

Acquired Defense:The adaptive/specific defenses: Third line of defense: Two branches of adaptive immunity - ________ involving B-lymphocytes, plasma cells, and antibodies.

antigen challenge

Active immunity: First response = ______

anamnestic response

Active immunity: second response also called "memory response" = _____

Opsonization

Antibodies: Fc region (of constant region) actions: ________: • Fc region of certain antibody classes makes it more likely target cell will be "seen" by phagocytic cells • Some phagocytes have receptors for these Fc regions - Bind to Fc region and engulf antibody and the antigen the antibody is attached to

Complement fixation

Antibodies: Fc region (of constant region) actions: _________: Fc region of IgG and IgM can bind complement for activation (classical complement activation).

Activation of NK cells

Antibodies: Fc region (of constant region) actions: ___________: • Fc region of some antibodies (IgG) trigger NK cells to release cytotoxins • This destroys abnormal cells through antibody-dependent cell-mediated cytotoxicity (ADCC)

immunoglobulin

Antibodies: __________ (Ig) proteins produced against a particular antigen - Antibodies "tag" pathogens for destruction by immune cells - Good defense against viruses, bacteria, toxins, yeast spores - Most effective at targeting extra-cellular pathogens.

IgM

Antibodies:Five classes of immunoglobulins: _____ is found mostly in blood - Most effective at agglutination and binding complement - Responsible for rejection of mismatched transfusions

IgA

Antibodies:Five classes of immunoglobulins: ______ is found in areas exposed to environment (mucous membranes) - Produced in mucus, saliva, tears, breastmilk - Protects respiratory and GI tract from infection - Helps prevent pathogens adhering to and penetrating epithelium - Especially good at agglutination

IgG

Antibodies:Five classes of immunoglobulins: ______ make up 75-85% of antibodies in blood and predominant antibody in other body fluids - Can participate in all types of antibody actions - Can cross placenta and cause hemolytic disease of newborn -Can neutralize snake venom

IgE

Antibodies:Five classes of immunoglobulins: _______ usually formed in response to parasites and in allergic reactions - Otherwise low rate of synthesis - Causes release of products from basophils and mast cells - Attracts eosinophils Antibodies

IgD

Antibodies:Five classes of immunoglobulins: _________ is found mostly on the surface of mature, naïve B cells - Functions as antigen-specific B-lymphocyte receptor - Identifies when immature B-lymphocytes ready for activation

Agglutination

Antibody function: _______ (clumping)- Antibody cross-links antigens of foreign cells causing clumping • Especially effective against bacterial cells • This slows down spread and allows other immune cells to destroy the pathogen

Precipitation

Antibody function: _______- Antibody cross-links circulating antigens (like viral particles) - Forms antigen-antibody complex (immune complex) that becomes insoluble and precipitates out of body fluids - Precipitated complexes engulfed and eliminated by phagocytes

Neutralization

Antibody function: _______- Antibody physically covers antigenic determinant of pathogen. - Makes it ineffective in establishing infection • For example antibody could cover region of virus used to bind cell receptor

Immunogen

Antigens: _______: antigen thatinduces an immune response

Antigenic determinant

Antigens: _________- Also known as epitope - Specific site on antigen recognized by immune system - Pathogenic organisms can have multiple determinants

Immunogenicity

Antigens: __________: ability to trigger response • Increases with antigen's degree of foreignness, size, complexity ,or quantity.

Clonal expansion

B cell multiplies itself, forming clones in response to antigen binding (__________) - All cells produced have same BCR that matches specific. antigen

plasma cells

Clonal expansion: -Most B cells differentiate into _______ cells that produce antibodies to that specific antigen.

Memory B lymphocytes

Clonal expansion: -remainder of B cells that arent plasma cells become ________. • Retain BCRs and activate with re exposure to same antigen • Have much longer life span than plasma cells

exudate

Fluid (_______) moves from blood to injured or infected area during Inflammation. This material is called....

cardinal

Four ______ symptoms of inflammation are rubor, calor, tumor, dolor (redness, heat, swelling, and pain)

• Hypersensitivities • Tissue rejection • Immune system disorders

How can the immune system be harmful to the body?

B-Cell Receptors

Humoral immunity: B cells contain different _______ (BCR) that can bind to one specific antigen - B lymphocyte directly binds antigen • Usually encounters antigen in a secondary lymphatic organ and is activated.

Second signal

Humoral immunity: B-Cell Receptors: _______: • Activated helper T-cell releases IL-4, stimulating B-lymphocyte • B cell usually requires T-cell in order to be activated

First signal

Humoral immunity: B-Cell Receptors: _______: • Intact antigen binds to BCR, cross-linking 2 BCRs • Stimulated B-cell engulfs, processes, and presents antigen to helper T-cell for recognition

complement and interferons

Innate Defense: Second Line of Defense:: -Protective proteins: ______ and ______ -They're antimicrobial proteins

First

Innate Defense: The nonspecific defenses: ______ line of defense: - Barriers to entry: physical and chemical

Second

Innate Defense: The nonspecific defenses: ______ line of defense: internal processes - Phagocytic white blood cells - Inflammatory response - Protective proteins: complement and interferons.

Antibody titer

Plasma cells: ________: circulating blood concentration of antibody against a specific antigen.

Onset

Stages of fever: - ______: temperature begins to rise • Hypothalamus stimulates constriction of dermal BV (less heat loss) • Shivering of muscle generates more heat (may be in response to chills)

Stadium

Stages of fever: _______: elevated temperature is maintained • Metabolic rate increases to promote elimination of harmful substance • Liver and spleen bind zinc and iron thereby slowing microbial reproduction

Defervescence

Stages of fever: ________: time when temperature returns to normal • Hypothalamus no longer stimulated by pyrogens • Prostaglandin release decreases • Hypothalamus stimulates mechanisms to release heat - Vasodilation, sweating

Physical barriers

The first line of defense: ______ to prevent pathogen invasion - Skin - few microbes can penetrate intact skin - Tears, saliva and urine physically flush out microbes - Mucous membranes line the respiratory, digestive, reproductive, and urinary tracts - form a physical barrier - Normal flora - normal microbes who reside on the barriers and "crowd out"the pathogenic microbes

Chemical barriers

The first line of defense: ________ - Skin releases antimicrobial substances • Dermicidin, lysozyme, sebum, defensins - Mucous membranes produce mucus and release antimicrobial substances • Defensins, lysozyme, IgA - Tears, sweat, saliva and secretions of the oil glands also contain antimicrobial substances like lysozyme - Acidic pH of the stomach and vagina kills or deactivates microbes

NK

The second line of defense: Apoptosis-inducing cells: ______ (natural killer) cells: destroy unhealthy/unwanted cells via apoptosis - Apoptosis is cell death that causes shriveling rather than lysis - Form in bone marrow, circulate in blood, and accumulate in secondary lymphatic structures • Perform immune surveillance—patrol the body, detect unhealthy cells - They destroy virus-infected cells, bacteria-infected cells, tumor cells, cells of transplanted tissue - They kill by releasing cytotoxic chemicals directly into the cell • Perforin creates a transmembrane pore in unwanted cell • Granzymes enter pore and cause apoptosis of cell

Fever

The second line of defense: Fever: _____ (pyrexia): abnormally elevated body temperature - 1°C or more from normal (37°C) - Results from the release of pyrogens (cytokines like IL-1 etc.) from immune cells or infectious agents • Hypothalamus releases prostaglandin E2, raises temperature set point leadingto fever

Heparin

The second line of defense: Proinflammatory chemical secreting cells: Basophils and mast cells: -contain secretory granules: - _______ acts as an anticoagulant

Histamine

The second line of defense: Proinflammatory chemical secreting cells: Basophils and mast cells: -contain secretory granules: -_______ increases vasodilation and capillary permeability

chemotactic

The second line of defense: Proinflammatory chemical secreting cells: Basophils and mast cells: They contain secretory granules • The chemicals released from the granules are ________. -They attract immune cells to the site and increase movement of fluid from blood to injured tissue

Eicosanoids

The second line of defense: Proinflammatory chemical secreting cells: Basophils and mast cells: ______ released from their plasma membrane also increase inflammation

Basophils and mast cells

The second line of defense: Proinflammatory chemical secreting cells: _____ and ______ promote inflammation. - Basophils circulate in the blood - Mast cells reside in connective tissue, mucosa, internal organs

Eosinophils

The second line of defense:Parasitic destroying cells: ______ attack multicellular parasites - Degranulate, releasing enzymes and other toxic substances • Can release proteins that form transmembrane pores in parasite - Participate in immune responses of allergy and asthma - Engage in phagocytosis of antigen-antibody complexes

Neutrophils and macrophages

The second line of defense:Phagocytic white blood cells: _____ and ______ destroy engulfed particles • Intake vesicle fuses with lysosome forming phagolysosome • Digestive enzymes break down the unwanted substances • Respiratory burst produces reactive oxygen-containing molecules that help destroy the microbes • Degraded residue is released by exocytosis

Dendritic cells

The second line of defense:Phagocytic white blood cells: _______ destroy particles and then present fragments • Antigens are presented on dendritic cell surface to T-lymphocytes - Necessary for initiating adaptive immunity - Macrophages can also perform antigen presentation

IFN-α and IFN-β

The second line of defense:Protective antimicrobial proteins Interferons: ____ and _____ produced by leukocytes and virus-infected cells -Bind to neighboring cells and prevent their infection and signal NK cells to destroy virally-infected cells • Trigger synthesis of enzymes that destroy viral nucleic acids, inhibit synthesis of viral proteins.

IFN-g

The second line of defense:Protective antimicrobial proteins Interferons: ______ produced by T-lymphocytes and NK cells • Stimulates macrophages to destroy virus-infected cells

Interferons

The second line of defense:Protective antimicrobial proteins: _________: - Cytokines produced by virus infected cells sent out to warm neighboring cells and nonspecifically impede viral spread.

Margination

The second line of defense:The Inflammatory response: -Recruitment of leukocytes _______: leukocytes stick to endothelial CAMs

Pus

The second line of defense:The Inflammatory response: -Recruitment of leukocytes: "______" is the accumulation of destroyed pathogens, dead leukocytes, macrophages, cellular debris.

Diapedesis

The second line of defense:The Inflammatory response: -Recruitment of leukocytes: _______: leukocytes migrate through and escape blood vessel walls

Chemotaxis

The second line of defense:The Inflammatory response: -Recruitment of leukocytes: _______: leukocytes migrate toward chemicals released from damaged, dead, or pathogenic cells

Inflammation

The second line of defense:The Inflammatory response: _______: an immediate response to ward off unwanted substances - Local, nonspecific response of vascularized tissue to injury

active and passive

There are two types of immunity: _____ and _____

Kinins

_____ stimulate pain receptors, increase capillary permeability, increase production of CAMs by capillary cells

Adaptive immunity

______ activation requires contact between lymphocyte and antigen

Body/self

______ antigens are typically recognized as normal and do not bind and set off immune response - May inappropriately stimulate immune response in auto-immune disease

Clotting proteins

______ form clots that wall off microbes

Subacute hypersensitivities

_______ occurring within 1 to 3 hours - Induced by humoral immunity

Immunity

_______: Is the ability to combat pathogens and cancer • Can be brought about naturally through an infection or artificially through medical intervention

Cytokines

_______: small proteins that regulate immune activity - Produced by cells of both innate and adaptive immune system - Chemical messengers released from one cell that bind to receptors of target cells • Can act on cell that released it (autocrine); on local cells (paracrine); or on distant cells after circulating through blood (endocrine) • Have short half-life

Antigen

_______: substance that can be recognized by and bind to a T-lymphocyte or antibody - Usually a protein or large polysaccharide - Examples of antigens • Protein capsid of viruses • Cell wall of bacteria or fungi • Bacterial toxins • Abnormal body proteins or tumor antigens

Acute hypersensitivities

________ (allergies) occurring within seconds • Severe allergies may result in systemic vasodilation and inflammation - Anaphylactic shock - Induced by humoral immunity

Foreign/abnormal

________ antigens bind and set off immune responses

Immunodeficiency

________ disease: - A disease in which the immune system is compromised and thus unable to defend the body against disease - Examples: AIDS and SCID

Delayed hypersensitivities

________ occur within 1 to 3 days - Involve cell-mediated immunity

Plasma cells

________ synthesize and release antibodies - The cells remain in the lymph nodes - They produce millions of antibodies during 5-day life span • Antibodies circulate through lymph and blood until encountering antigen

Third line of defense

________: - Helps protect us against specific pathogens when nonspecific defenses fail - Helps protect us against cancer - Depends on the action of lymphocytes - Immune response consists of lymphocytes and their products - Longer response time than innate immunity • Since it takes days to weeks to develop, adaptive immunity is considered the third line of body's defense.

Hypersensitivities

________: • Abnormal and exaggerated response of immune system to antigen

Tissue rejection

________: • Cytotoxic T cells respond to tissue that is not recognized as "self" tissue • This is a normal function of the immune system but it is harmful when it affects a transplanted organ or tissue • This can be controlled by giving patients immunosuppressive drugs and by transplanting organs that have the same MHC proteins in the donor and recipient • Currently, trying to grow organs in the lab that can be transplanted with less rejection

Active immunity

________: • Direct contact with a particular pathogen causes the body to make antibodies against that particular antigen • Induced through natural infection or artificially through vaccination • The first exposure causes a slower shorter lasting response • Secondary exposure causes a rapid, stronger response - Anamnestic response • This type of immunity is usually long-lasting - May need "Booster" • It depends on memory B and T

Chronic Inflammation

________: • Inflammation continuing for longer than two weeks• Characterized by macrophages and lymphocytes(not neutrophils) • Can occur from overuse injuries - E.g., tennis elbow or shin splints • May occur if acute inflammation unable to eliminate pathogen • May be due to autoimmune disorder • Can lead to tissue destruction and scar tissueformation

Adaptive immunity

________: acquired/specific immunity - Response to antigen involves specific T- and B-lymphocytes • A particular cell responds to one specific foreign substance but not another - Takes several days to be effective

Antigen presentation

________: cells display antigen on plasma membrane so T-cells can recognize it and bind to it.

Helper T cells

________:- Migrate to infected site - Release IL-2 and other cytokines - Help activate B-lymphocytes - Activate cytotoxic T-lymphocytes with cytokines - Stimulate activity of innate immune system cells

Autoimmune diseases

_________ : - A disease in which cytotoxic T cells or antibodies attack the body's own cells as if they were foreign Examples: lupus, myasthenia gravis, and rheumatoid arthritis

Cytotoxic T cells

_________- Migrate to infected site - Destroy infected cells that display the antigen • Make physical contact with unhealthy or foreign cell initiating the "kiss of death" • After recognizing antigen, cytotoxic T-cell releases granules containing perforin and granzymes (cytotoxic chemicals) • Perforin forms channel in target cell membrane • Granzymes enter channel and induce death byapoptosis

Passive immunity

_________: • An individual is given antibodies against a particular antigen - Obtained from another individual • Can occur naturally via transfer of antibodies from mother to fetus(through placenta or milk) • Can occur artificially when serum transferred from one person to another (antibodies to snake venom) - Neither form of passive immunity produces memory cells • This type of immunity is short-lived

Innate immunity

_________: present at birth and mostly unchanged through life - Protects against variety of different substances (nonspecific) • No prior exposure to substance necessary - Includes barriers of skin and mucosal membranes, non-specific cellular and molecular internal defenses - Respond immediately to potentially harmful agents

Acquired immunodeficiency syndrome

___________ (AIDS)- HIV - human immunodeficiency virus - Destroys helper T cells and macrophages - Symptom free for years - Develop opportunistic infections

Cytokines effects

• Cell communication (including non-immune cells, e.g., neurons) • Controlling development and behavior of immune cells • Regulating inflammatory response • Destroying cells