Chapter 12: Adaptive Immunity
IGD
.2% of IGs, antigen receptor of surface of B cells, monomer
B-cell deficiencies
(53%) (b-cells produce antibodies) Agammaglobulinemia
T-cell deficiencies
(7%) AIDS
Cell-Mediated
(Adaptive Immunity) that involves T cells (t cells recognize antigens through receptors)
Humoral
(Adaptive Immunity) that involves antibodies produced by B cells
cd markers
(cluster of differentiation markers); required for antigen recognition; found on T lymphocytes; CD8 marker is found on cytotoxic T cells and suppressor T cells, and CD4 is found on helper T cells; CD8+ cells recognize antigens bound to MHC I proteins while CD4+ cells recognize antigens bound to MHC II proteins.
-peptidoglycan & LPS -double-stranded DNA
-Two bacterial PAMPs: -Viral PAMPs:
How do memory B cells contribute to the secondary immune response? What is class switching?
...
Cell Mediated Response
trigger T lymphocytes recognize and destroy abnormal/infected host cells
IGG
triggers complement cascade resulting in cytolysis of a pathogen, transfers passive immunity to a fetus
Which class of antibody is found in mucous membranes?
IgA
Which classes of antibody are found on the surface of B cells?
IgD and IgM
Which class of antibody is produced in response to parasites and allergens?
IgE
Which class of antibody can cross from mother to fetus?
IgG
Which class of antibody is the most abundant in circulation?
IgG
5 Classes of Antibodies
IgG IgM IgA IgD IgE
Which classes of antibody can activate the classical complement pathway?
IgG and IgM
Five classes of Antibodies
IgG- monomer IgM - pentamer IgA - dimer IgD - monomer IgE - monomer
Which class of antibody is the first to be produced during a humoral immune response?
IgM
B Cell Development
Immature B cells: Limitless assortment of B-cell receptors is randomly generated. Naive B cells:each cell is programmed to recognize a specific epitope on an antigen; B-cell receptors guide that recognition.
structure of antibodies
two heavy and 2 light chains linked by disulfide bonds; shaped like a Y; antigen binding regions on branches of Y ("variable" regions)
1. body cells (self) 2. foreign material (nonself)
Immune cells identify two types of cells in the body:
Class II genes:
Immune regulatory markers found on macrophages, Dendritic cells, and B cells, and are involved in presentation of antigens to T cells
Naturally acquired active immunity
Immune response mounted against antigens encountered in daily life.
Naturally acquired passive immunity
Immunity acquired passively through the antibodies passed from mother to child (via breast milk or across the placenta).
Artificially acquired passive immunity
Immunity acquired through the direct injection of antibodies into a patient, refers to humoral antibodies acquired by injection; can last for a few weeks, Injection of Ab (antibodies)
Active Natural Immunity
Immunity that lasts for a certain period after recovering from an infectious disease; childhood viral infections usually result in lifelong immunity
Antibody involved in allergies
Immunoglobulin E
1st Antibody produced
Immunoglobulin M
Immunoglobulin E
Immunoglobulin found in very low concentrations in serum (<1%) and generally function as signal molecules. May attach to the receptors found on eosinphils, which release chemicals that damage parasites.
Immunoglobulin M
Immunoglobulin subunits combine to form a large 5-unit polymer. Due to its large size it is particularly suited for complement activation (and may also be involved in agglutination and neutralization).
Be able to describe the differences between a primary and secondary humoral immune response including the time involved to produce antibody, the types of antibody produced and the relative amounts of the antibodies produced.
In a primary response it takes 10-14 days for a substantial amount of antibodies to accumulate. There is a slow but steady increase in antibody molecules. In a secondary response the response time is much faster and more effective. More antibodies are produced
How does an adaptive immune response differ from innate immunity?
In adaptive immunity the response is to a specific antigen. The body creates memory.
How do neutralization and immobilization help to prevent the invasion and/or spread of pathogens?
In neutralization a toxin or virus coated with antibodies cannot attach to cells and is said to be neutralized. In immobilization the binding of antibodies to flagella interferes with a microbe's ability to move; binding to pili prevents it from attaching to surfaces.
Active Immunity
Individual has clones of memory B and T Cells
Passive Immunity
Individual receives antibodies from another individual
Humoral immunity
uses antibodies in extracellular fluids such as mcucus secreations, blood plasma, and lymph to combat antigens These antibodies are produced by B cells(B lymphocytes) B cells mature in the bone marrow Effective mostly against bacteria, bacterial toxins, and viruses
Local or systemic
Inflammation can be:
lymphocytes, fibroblasts, & macrophages
Interferon alpha (INF-α) & interferon beta (INF-β) is produced by (3):
activated T cells & natural killer (NK) lymphocytes
Interferon gamma is produced by:
Passive Artificial Immunity
Involves a preparation that contains specific antibodies against a particular infectious agent; human serum from donor blood and immune serum globulins are used commonly
Phase I Trials
Involves a small number of healthy, uninfected participants and primarily tests the safety of the vaccine and the extent of immune response (dose and scheduling); usually lasts 12-18 months
Exploratory Stage
Involves basic laboratory research and often lasts 2-4 years
Phase II trials
Involves hundreds of participants with varying degrees of risk to better characterize the safety of the vaccine and the immune response being caused by the vaccine; goals are to study the candidate vaccine's safety, immunogenicity, proposed dose, schedule of immunizations, and method of delivery; can last 2 or more years
Phase III Trials
Involves several thousand high-risk volunteers to further assess if the vaccine works and is double-blinded; can last 3-5 years
IgM
It is the first immunoglobulin to appear on the surface of B cells and the first antibody secreted during an immune response. It is secreted in pentameric form.
Characteristic of Primary Response
Lag period of 10 to 12 days occurs before antibody detection in blood Net result is slow steady increase in antibody titer
Diapedesis
Last step in extravasation, migration of WBCs from blood vessels into tissues:
Memory B cells
Long-living cells that have complementary BCRs to the specific epitope that triggered the B cells' production. These cells persist for more than 20 years and may trigger the production of antibodies should that specific epitope be encountered in the future.
What type of cells are B and T Cells?
Lymphocytes
Helper T cell (Th1)
Lymphocytes that assist cytotoxic T cells and innate macrophages.
Cytotoxic T cells
Lymphocytes that directly kill cells infected with viruses or other intracellular pathogens.
Helper T cell (Th2)
Lymphocytes that work in conjunction with B cells; produce various protein messengers, known as cytokines, that decide which immune response is necessary.
Phagolysosome
Lysosome migrate & fuse with the phagosome to become a:
Does MHC 1 present endogenous or exogenous antigens? MHC 2?
MHC 1-endogenous angitens MHC 2-exogenous antigens
IgM
MONOMER Immunoglobin (messenger) antibody, the first antibody made when the host is exposed to the antigen
To return lymph to the circulation in one direction
Main function of the lymphatic system:
Class I genes:
Markers that appear on all nucleated cells that identify self and allow for recognition of immune reactions
Recognize Self
Maturation of T-Cells involves training them to do what?
B- Cells
Mature in the Bone Marrow, forms plasma cells, cells that develop from stem cells in bone marrow or liver. They are transported to the lymph nodes and slpeen where they are used as antigen receptors (antigen binding sites), each one produces only one specific antibody
T- Cells
Mature in the Thymus
What is humoral immunity? What cells are associated with humoral immunity? What type of antigen causes a humoral immune response? What are the products of a humoral immune response?
Mediated by B cells Primarily against extracellular antigens Antibodies and Memory B cells are the product
What is cell mediated immunity? What cells are associated with cellular immunity? What type of antigen causes a cell mediated immune response? What are the functions of cytotoxic T-cells and activated macrophages in cell mediated immunity?
Mediated by T cells Primarily against intracellular antigens Cytotoxic T-cells, activated macrophages
Macrophages; by various inflammatory mediators
Monocytes are transformed into _______ by various:
IgE
Monomer 0.002% of serum antibodies On mast cells, on basophils, and in blood Allergic reactions; lysis of parasitic worms Half-life = 2 days
IgD
Monomer 0.2% of serum antibodies In blood, in lymph, and on B cells On B cells, initiate immune response Half-life = 3 days
IgG
Monomer 80% of serum antibodies Fix complement In blood, lymph, and intestine Cross placenta Enhance phagocytosis; neutralize toxins and viruses; protect fetus and newborn Half-life = 23 days Appears in second immune response
IgG
Most Common and Longest Lasting Antibody
Innate immunity
Native from birth; primordial; does not change; immediate response; no specific memory
(Four types of) adaptive immunity
Naturally acquired active from actual disease, naturally acquired passive immunity transferred from mother to fetus, artificially acquired active immunity from vaccination, artificially acquired passive immunity from human or animal donor
Types of Adaptive Immunity
Naturally acquired active immunity Naturally acquired passive immunity Artificially acquired active immunity Artificially acquired passive immunity
Deployment of T Cells
Naïve T cells leave thymus and colonize lymphatic tissues and organs
Protective Outcomes of Antibody-Antigen Binding
Neutralization Immunization Opsonization Complement Activation Aggulation and Precipitation Antibody Dependent Cytotoxicity (ADCC) - Antibody binds to the cell surface then natural killer cells attach to FC region of antibody and kill cell
opsonization
what is the term for coating of a pathogen with an antibody to cause phagocytosis?
variable regions
what part of an antibody binds an antigenic determinant?
Major Histocompatibility Complex
One set of genes that is responsible for human cell markers/receptors; found on all cells except RBCs; vital for recognition of self by immune system and rejection of foreign tissue
Which functions lead to the destruction of antigens bound by antibodies? How do these functions operate?
Opsonization, complement system activation, cross-linking and antibody-dependent cellular cytotoxicity (ADCC).
Crisis of a fever
Other name for when a fever "breaks"
IgG
PENTAMER Immunoglobin G antibody, used when IgM wears off. IgG last much longer and represents immunity or having the disease in the past
IgM
Pentamer 5-10% of serum antibodies Fix complement In blood, in lymph, and on B cells Cannot cross placenta Agglutinate microbes First Ab produced in response to infection Half-life = 5 days
Secondary Lymphoid Organs
Peyer's patches, Lymph nodes, spleen, tonsils, adenoids, appendix
Pseudopods; phagosome
Phagocytes: Once phagocyte has made contact with a microbe, it extends its ___________ to enclose & internalize it in a _________.
1. oxygen-dependent system (respiratory burst) 2. liberation of lactic acid, lysozyme, & nitric oxide
Phagocytosis: 2 separate systems of destructive chemicals=
Hydrogen peroxide, singlet oxygen, hydroxyl free radical
Phagocytosis: Respiratory burst releases these (3):
B Cell Proliferation and differentiation
Plasma cells(Effector B cells): These cells secrete large quantities of antibody molecules that bind antigen X. Memory B cells: These long-lived cells recognize antigen X when it is encountered again.
Killed Vaccines
Prepared by cultivating the desired strain of bacterium or virus and treating them with chemicals, radiation, heat, other some other agent that does no destroy antigenicity; stimulates immunity but pathogen cannot multiply
Artificial Immunity
Produced purposefully through medical procedures
B-lymphocyte response:
Production and activities of antibodies
Hematopoiesis
Production of blood cells
Lymphocytes
Programmed to remember previous encounters with antigens and respond accordingly
Goal of vaccination
Provides a robust primary response and a memory response by priming the immune system for future exposure to a pathogen
combinatorial associations
Random association rearrangement of the protein chains (Different L chains with different H chains)
Characteristics of inflammation
Redness, heat, sweat and pain
-Vagina secretions provide an acidic environment -Semen contains antibacterial chemicals
Reproductive chemical defenses (in male and female):
function of constant region
Responsible for activities of antibodies like activating complement or attaching to various kinds of WBCs
Naturally acquired active immunity
Resulting from infection - exposed or get infections so u will make antibodies
by increased circulation & vasodilation in the injured tissue
Rubor caused by:
Rubor=Redness Calor=Warmth Tumor=Swelling Dolor=Pain
Rubor= Calor= Tumor= Dolor=
Activation of complement
when infectious agents are coated with reactive proteins that cause IgG and IgM antibodies to attach to the agent resulting in inlammation, cell lysis and ingestion of phagocytosis
APCs carry antigens to lymphoid tissues..
where they "teach" T and B cells to recognize the antigen
Lymph nodes
Secondary lymphoid organs where lymphocytes are housed, lying in wait for a foreign invasion. There are hundreds located throughout the body, but the large majority are concentrated in the cervical (neck) region, inguinal region (groin), axillary (armpit), and abdominal region. They are sites that facilitate interactions among immune cells and between immune cells and material in the lymph arriving from throughout the body.
IGA
which class of antibody is in mucus membranes and body secretions?
T-cells
Secrete cytokines to help destroy pathogens, but do not produce antibodies
helper T cell
which type of T cell is a CD4?
secondary response
which type of immune response produces mostly IGG?
malaise, body aches & tiredness
Side effects of fever (3)
1. Chemotaxis 2. Ingestion 3. Engulfment & phagosome formation 4. Phagolysosome formation & killing 5. Destruction 6. Excretion
Six events of phagocytosis:
What are the physical barriers in innate immunity
Skin and mucous membranes
Adjuvant
Small molecules added to a preparation of immune system stimulating components that enhances immunogenicity by a number of mechanisms
Haptens:
Small molecules that are too small to elicit an immune response alone but when linked to a larger carrier molecule, they elicit an immune response; typically, it is the epitope
Interferons
Small proteins produced naturally by certain white blood & tissue cells
Five Attributes of Adaptive Immunity
Specificity, Inducibility, Clonality, Unresponsiveness to self (won't take out normal microbiota), Memory
Vasodilation and Blood Vessel Permeability
Stage one of inflammation - Blood volume is increased but the rate is slowed
Phagocyte Migration and Phagocytosis
Stage two - phagocytes move onto the scene
Whole Cell Vaccines
Stimulate immunity but cause no disease
T Cell Activation
T Cell Binds to another APC Protein = Costimulation •Clonal selection gives rise to a clone of identical T cells programmed against the same epitope
What type of cell is the CD marker associated with?
T cell
cell-mediated immunity
T cells (specialized lymphocytes) act against foreign substances; effective against fungi, protozoa, helminths, cancer, and skin and organ transplants
Positive T Cell Selection
T cells multiply and form clones of identical T cells programmed to respond to a specific antigen
cellular immune response
T cells produce, recognize one antigenic epitope, macrophage and dendritic cells carry antigen to T cell;
Negative T Cell Selection
T cells that react to self antigens undergo anergy (clonal deletion)
bone marrow stem cells give rise to
T cells, which mature in the thymus gland
True
T or F: Antimicrobial proteins can have chemotactic factors
False
T or F: Defensins are small peptides that work against only a few pathogens
True
T or F: Interferons work against viruses
True
T or F: Neutrophils can kill bacteria by nonphagocytic mechanisms.
True
T or F: Pyrogens affect the hypothalamus, causing elevation of the internal body temperature.
False
T or F: The alternative pathway for complement activation is more effective than the classical pathway.
True
T or F: cells possess PRRs whether they have encountered PAMPs before or not
TCR's (T Cell Receptors)
T- Cells have what on their cytoplasmic membrane?
Memory T- Cells
T- Cells which persist for months or years in lymphoid tissue and are immediately functional upon subsequent exposure to epitopes that are specific to it's TCR
Cytotoxic T- Cell
T-Cell that directly kills other cells
Helper T-Cell
T-Cell that helps regulate the activities of B cells and cytotoxic T-Cells
Regulatory T-Cell
T-Cell that represses adaptive immune response
Intracellular pathogens
TCR's act primarily against cells that harbor what (they are often viruses)?
Major Histocompatibility
TCR's only bind epitopes with what kind of protein?
1. Influx of fluid dilutes toxic substances 2. Fibrin clot can trap microbes to prevent further spread 3. Neutrophils aggregated at the inflamed site are involved in phagocytosing & destroying bacteria
The Benefits of Edema & Leaky Vessels (3):
What functions are associated with the Fab and Fc regions on an antibody?
The Fab region is the Antigen-Binding region that recognizes and binds to an epitope. The Fc region is the crystallizable region and is the stem.
Primary Lymphoid Organs
The Red Bone Marrow and Thymus are what?
IgE
The class of immunoglobulin having heavy chains. It is involved in allergic reactions.
Immunoglobulin A
The immunoglobulin most closely associated with various body functions. Often found as a dimer (2 monomers connected by a J chain), known as secretory IgA. Secretory IgA fights antigens through agglutination, neutralizing the antigens, making it of critical importance in protecting the body from infections.
Monocytes
The largest WBC:
Immunoglobulin G
The most common and longest lasting of the classes of antibodies found in the blood. These antibodies are the smallest of the antibody classes and are composed of a single, y-shaped monomer. They may leave the blood stream to bind with antigens located in tissues. Unlike other antibodies; may cross the placenta to protect the fetus during pregnancy.
What are the differences between a primary and secondary immune response?
The primary response is the body's first encounter to the antigen. Takes a week or more to respond. A secondary response occurs from subsequent exposure to the specific antigen. Caused by the rapid activation of long-lived memory cells
Naturally Acquired Immunity
The response against antigens encountered in daily life
1. the thymus 2. lymph nodes, tonsils & spleen 3. lymphoid tissue of gut & respiratory mucosa
The reticuloendothelial system includes (3):
antigen-binding site
The site on an immunoglobulin or T-cell receptor molecule that binds specific antigen.
epitope
The specific site on an antigenic molecule that binds to a T cell receptor or to an antibody.
Epitope:
The structural part of an antigen molecule that a lymphocyte recognizes and responds to
What happens during cross-linking?
The two arms of an antibody can bind separate but identical antigen molecules, linking them. The overall effect is that large antigen-antibody complexes form creating big "mouthfuls" of antigens for phagocytic cells to engulf.
How many chains and of what type are found in an antibody monomer? What portion of an antibody determines its class? What is the importance of the variable regions on the chains in an antibody molecule?
There are two heavy chains and two light chains. The constant region of the heavy chain determines the class of antibody. The variable region accounts for the antigen-binding specificity.
Macrophages
These WBCs arrive after neutrophils, when the attack is winding down:
Granulocytes; lobed nucleus
These WBCs have colored granules in the cytoplasm & a ______ nucleus
Agranulocytes; round nucleus
These WBCs have no granules & a ______ nucleus
T- Cells
These are produced in the red bone marrow and mature in thymus
Digestive, urinary, respiratory, and reproductive
These are the tracts that contain physical barriers to pathogens (4):
Humoral and Cell Mediated
These are two types of adaptive immune responses.
Natural killer cells (NKCs)
These come from the same lymphoid cells as T & B cells, but are not 'antigen-specific'
Interferon gamma
These interferons are present later in the adaptive immune response:
Interferon alpha (INF-α) & interferon beta (INF-β)
These interferons are present within hours of a viral infection:
Pattern recognition receptors (PRRs)
These recognize & bind PAMPs; amplifies & orchestrates a specific immune response
The circulatory & lymphatic systems
These two systems interconnect with & complement each other
Monocytes & Macrophages
These types of WBC lives as phagocytes for a few days after they are discharged from the bone marrow (2):
Alternative pathway
This complement pathway is activated when components of the complement pathway recognize & bind to pathogen membranes
Classical pathway
This complement pathway is initiated either by the foreign cell membrane of a parasite or a surface antibody
Lymphatic Vessels and Flow
This conducts lymph from tissues and returns it to the circulatory system.
Lysozyme
This is found in tears & saliva
Lymph
This is liquid with similar composition to blood plasma and arises from fluid leaked from blood vessels into surrounded tissues.
Second line of defense
This line of defense includes internalized system of protective cells & fluids
First line of defense - Physical barriers
This line of defense includes mucous membranes of the digestive, urinary, respiratory & reproductive tracts & the eye cover body cavities that are open to the outside environment
Cell Mediated Immune Response
This responds to intracellular pathogens and abnormal body cells; most common is virus; response is also effective against cancer cells, transplanted cells, intracellular protozoa and intracellular bacteria
Humoral Immune Response
This response is mounted against exogenous pathogens and activates only in response to specific pathogens; Two types: T-Independent and T-Dependent
Macrophages
This type of WBC is a dynamic scavenger through the RES:
Dendritic cell
This type of WBC presents foreign antigens to T cells in 3rd line of defense
Macrophages
This type of WBC processes foreign substances & prepare them for reactions with B & T lymphocytes
Second line of defense
This type of defense includes inflammation & phagocytosis
Third line of defense
This type of defense is acquired on an individual basis as each foreign substance is encountered by lymphocytes
Third line of defense
This type of defense provides long-term immunity
Dendritic cells
This type of physical barrier exists below the mucus epithelium to phagocytize invading microbes
1. to mobilize & attract immune components to the site of injury 2. to set in motion mechanisms to repair tissue damage & localize & clear away harmful substances 3. destroy microbes & block their further invasion
Three chief functions of inflammation:
Epitope
Three dimensional Regions on Antigens- attach it to B and T Cells
1. trauma from infection 2. tissue injury or necrosis due to physical or chemical agents 3. specific immune reactions
Three factors that elicit inflammation:
1. Return extracellular fluid to the circulatory system 2. Act as a 'drain-off' system for the inflammatory response 3. render surveillance, recognition, & protection against foreign materials
Three functions of lymphatic system:
1. survey the tissue & discover microbes, particulate matter, & injured or dead cells 2. ingest & eliminate these materials 3. extract immunogenic information (antigens) from foreign matter
Three general activities of phagocytosis are:
Skin surface Mucous membranes Neutrophils
Three placed antimicrobial peptides are found:
1. rapid heart rate 2. elevated respiratory rate 3. lowering of seizure threshold
Three side effects to moderate fever that may require medical attention in some patients:
Diapedesis
Tissue repair
Naturally acquired passive immunity
Transplacental or via colostrum - get from mother
Cell-mediated immune responses
Triggered in response to endogenous antigens (i.e.- viruses). They are also mounted against other intracellular invaders (protozoa or bacteria) and cancer cells.
fluid escaping into the tissues
Tumor caused by:
1. bind to interferon receptors on cytoplasmic membranes of neighboring cells 2. triggers the production of antiviral proteins (AVPs) that bind to viral nucleic acid
Two functions of INF-α & INF-β
1. stimulates the activity of macrophages & neutrophils (also called macrophage activating factor) 2. activated phagocytic activity
Two functions of INF-γ
Natural and Artificial Immunity
Two types of immunity that can be acquired in someone's lifetime
Interferon
Type of cytokine that act as antiviral signals.
Interleukin
Type of cytokine that acts as a signal to other leukocytes.
B cell receptors
Type of surface protein that is located on the cell surface of a B cell (~500,000 identical copies); the shape of the antigen-binding site is determined by the random sorting of immunoglobulin regions of a B cell's DNA. .
How do B cells recognize exogenous antigens? How many different epitopes can be recognized by a single B cell?
Use IgD and IgM to bind extracellular antigens Each B cell will only recognize one epitope
Active Artificial Immunity
Vaccination
IgM, IgG, IgA, IgE, IgD
What are the five classes of Antibodies (B-cells)
Plasma Cell
What is an activated B Cell referred to as?
Immunoglobulin
What is secreted by activated B/Plasma Cells?
Similar to the alternative pathway except that lectins binds to mannose residues on the surface of pathogens in order for the classical pathway to proceed
What is the Lectin pathway?
Secondary Lymphoid Organs
What type of organs are the Lymph notes, Spleen, Tonsils, Mucosa Associated Lymphatic Tissue (MALT- Peyer's Patches)
-Proteins denature -nerve impulses inhibited =hallucinations, coma or death
What will happen if fever gets too high?
What happens during antibody-dependent cellular cytotoxicity? (ADCC)
When multiple IgG molecules bind to a virally infected cell or tumor cell, that cell becomes a target for destruction by NK cells. The NK cell attaches to the Fc regions of IgG and once attached, kills the target cell by delivering compounds directly into it.
Autoimmune diseases
When the immune system mistakenly attacking the body's own tissues & organs your body attacks your own cells Humoral or cell medicated response against self-antigen Grave's disease: excessive thyroid hormone production when antibodies react with the thyroid gland. Rheumatoid arthritis Systemic lupus erythematosus
respiratory mucosa
Where RES action takes place:
T- Cells
Which cells are Cell Mediated?
Alternative: doesn't require antibodies
Which complement pathway is quicker? why?
Blood cells Plasma Serum
Whole blood consists of (3):
Types of Vaccines
Whole cell vaccines: killed vaccines and live attenuated vaccines. Subunit Vaccines
antibody monomer
Y-shaped: V (variable) regions form the time, the C (constant) regions form the base and Fc (stem) region
shape of antibody
Y: variable regions
HCl
______ in the stomach gives protection against microbes
Lactic acid & electrolytes
_________ & _________ in sweat inhibits microbes
Antibiotic treatment; results in 'ill-trained' gut
________________ may cause immunologic disturbances in the gut
Memory Cell
a B-cell that was generated in the primary response but did not become an antibody producing plasma cell at that time.
epitope
a localized region on the surface of an antigen that is chemically recognized by antibodies; also called antigenic determinant
hapten
a low-molecular-weight substance that cannot cause the formation of antibodies unless combined with a carrier molecule; react with their antibodies independently of the carrier molecule
Host defenses
a multilevel network of innate, nonspecific protections & specific immunities referred to as the 1st, 2nd & 3rd lines of defense
epitope
a region of an antigen that stimulates an immune response
hapten
a small molecule that stimulates an antibody response when attached to a larger antigen
Reticulum
a support network of connective tissue fibers that originates in the cellular basal lamina, interconnect nearby cells & meshes with the massive connective tissue network surrounding all organs
Immunity
ability to ward off disease
Edema
abnormal accumulation of fluids
T cells are classified
according to their functions and cell-surface glycoproteins called CDs
Th2 cells
activate B cells (to produce antibody) and are associated with allergic reactions and parasitic infections
T Helper Cells
activate B cells to make antibodies and stimulate other immune cells to attack pathogens
T-Independent Antigens
activate B cells without TH cell help (ie LPS and some carbohydrates)
Th1 cells
activate cells involved in cellular immunity (CD8 cytoxic T cells)
Helper T-cells:
activate macrophages, assist B-cell processes, and help activate cytotoxic T-cells; often referred to as CD4 cells
T helper cells (CD4 T)
activated by MHC class 2 on APCs. After binding an APC, CD4 T cells secrete cytokines that activate other T and B cells
T cytotoxic cells (CD8 T)
activated by endogenous antigens and MHC class 1 on a target cell and are transformed into a CTL
fc region
activates complement cascade
Secondary (memory) Response
after subsequent exposure (stronger and more specific)
modes of action of antibody
agglutination, opsonization, neutralization, cytotoxicity, complement
Type of immune response
agglutinization
Peyer's patches
aggregations of lymphocytes in the small intestine
IGE
allergic reactions
IGE
allergic reactions, found on mast cells and basophils, reaction causes mast cells to release histamine and other chemical mediators
IGE
allergic responses and responses to worms
Hypersensitivity
allergy
Antibody titer
amount of antibody in serum, is the amount of Ab(antibodies) in serum. Gradually inclines and declines as the antigen is destroyed or neutralized.
an antigen-antibody complex forms when..
an antibody binds to its specific epitopes on an antigen
agglutination results when
an antibody combines with epitopes on two different cells
Natural Adaptive Immunity
an organism or toxin enters the body and produces an immune response
naturally acquired passive immunity
antibodies transferred from a mother to a fetus or to a newborn in colostrum; can last up to a few months
humoral immunity involves
antibodies; which are found in serum and lymph are produced by B cells
macrophage
antigen presenting cell
epitopes
antigenic determinants
clonal selection
antigens bind to specific receptors, causing a fraction of lymphocytes to clone themselves
Major Histocompatibilty Complex
antigens presented to MHC to decide if they are dangerous or not
Antigen
any compound that elicits an immune response, a substance that causes the body to produce specific antibodies or sensitized T cells, a chemical substance that causes the body to produce specific antibodies; proteins or large polysaccharides
IGG
appears second, makes up about 80% of IGs, monomer structure, easily crosses walls of blood vessels and enters tissues, crosses the placenta
Dendritic cells
are the primary APCs
IgE antibodies
bind to mast cells and basophils and are involved in removal or parasites and allergic reactions
complement activation
bind to pathogen and complement proteins
neutralization
block adhesion to cell tissues or action of toxins
salivary glands, tear ducts, intestine, & urinary tract
blockages in these increase risk of infection (4):
primary lymphoid organs
bone marrow and thymus
T cells
bone marrow, differentiate in thymus
the Fc region
can attach to a hot cell (phagocyte) or to complement
chemokines
cause leukocytes to migrate to an infection
antibodies that attach to microbes or toxins
cause neutralization
complement activation results in
cell lysis of opsonized antigens
T cells
cell type responsible for cellular immunity
In Antibody-Dependent Cell-Mediated Cytotoxicity
cells and macrophages lyse antibody-coated cells
agglutination
clumping of antigens with antibodies, making them non-functional and increasing their chance of being ingested, reduces number of infectious units to be dealt with
cytotoxicity
coat pathogen, bind macrophage that releases lytic enzymes
Opsonization Ex: antibody, complement -makes the microbe recognized by phagocytes
coating of foreign substances by serum components (2 examples?): -What is the purpose?
opsonization
coating to enhance phagocytois
Lymphatic System
collection of tissues and organs designed to bring B and T cells in contact with antigens
Antibodies
combine with antigens and bind to them Globular proteins produced in response to antigens, bind with foreign substances; called immunoglobulins (IGs) secreted by plasma cells (which are B cells fighting exogenous antigens); part of the humoral immune response like lock and key 2 light chains and 2 heavy chains 2 antigen bonding sites
IgM antibodies
consist of five monomers held by a joining chain; involved in agglutination and complement fixation
Live Attenuated Disease
contain live microbes whose virulence has been lessened/eliminated by modifying the growth conditions or manipulating microbial genes; advantages: viable microbes can multiply and produce infection like the natural organism, they confer long-lasting protection, they usually require fewer doses and boosters, they are particularly effective at inducing cell-mediated immunity; disadvantages: they require special storage facilities, they can be transmitted to other people, and they can mutate back to become virulent again
Eosinophilis
contains toxic compounds that are used to defend against parasites
overproduction of cytokines leads to
cytokine storm, which results in tissue damage
interleukins
cytokines that serve as communicators between leukocytes
CD8 (T cell)
cytotoxic T cells, form CTLs
Innate Immunity
defenses against any pathogen
Innate immunity
defenses against any pathogen
defensins
dermal cells, in the layer just below the dermis, secrete antimicrobial peptides called:
Cytotoxic T Cells
destroy abnormal human cells
Effector T cell
developed through clonal selection and carry out cell mediated immune responses
Activated B cells
differentiate into plasma cells and memory cells
IgA
dimer found in body secretions protects gastrointestinal tract of newborns
IGA
dimer of two antibody monomers
secretory IgA antibodies
dimers that protect mucosal surfaces from innovation by pathogens
GALT (Gut-associated lymphoid tissue)
discrete bundles of lymphocytes on or just beneath the intestinal mucosa:
proliferate & differentiate
during development, stem cells __________ & ____________ into the specialized form & function of mature cells
Activated macrophages are
effective phagocytes and APCs
B cells that recognize self are
eliminated by clonal deletion
Humoral Immunity
eliminates extracellular pathogens, mediated by B lymphocytes aka B cells
Class III genes:
encode proteins involved in the complement system
Dendritic Cells
engulfs foreign antigens and present to a different MHC
gene rearrangment
entire gene moved to a new location
Lysozome
enzymes in tears and saliva that breaks down cell walls
erythrocytes=RBCs leukocytes=WBCs thrombocytes=platelets
erythrocytes= leukocytes= thrombocytes=
secondary response
exposure after an initial exposure to an antigen: immunologic memory
IGM
first IG to appear in response to an antigen, 5-10% of all IG, the largest IG, a pentamer structure with five monomers held together with a polypeptide j chain, remains in blood and does not enter tissues
Ab Dependent Cytotoxicity
flags down immune system cells to destroy antigens too big for phagocytosis
Opsonization
flags down phagocytes to destroy cell
Anitgen
foreign particle that enters the body can be broken into epitopes
cytotoxic T cells
form CTLs
IgE
found on mast cells and basophils triggers release of histamine
bone marrow stem cells
give rise to B cells with IgM and IgD on their surfaces, they migrate to lymphoid organs in the periphery and fully mature to recognize specific epitopes
Dendritic Cells
have dendrite looking branches reaching out , Antigen-presenting cells, located mainly in lymphatic tissues and skin, that is particularly efficient in presenting antigens to naive helper T cells, thereby initiating a primary immune response.
CD4 (T cell)
helper T cells, activated macrophages
cytokines
how cells of the immune system communicate with each other
born with capacity (to form B cells with millions of possibilities)
how we form antibodies
two types of immunity
humoral, cell-mediated
Cytokines
hundreds of small active molecules constantly being secreted to regulate, stimulate, suppress, & otherwise control many aspects of cell development, inflammation, & immunity
Two types of cells resulting from activating B cells
immediate response cells that live a few days, memory cells that last years
Cellular Immunity
immune response that relies on T cells to destroy infected body cells
Secondary response
immune system remembers pathogen on subsequent exposure
naturally acquired active immunity
immunity resulting from infection; may be long-lasting
artificially acquired active immunity
immunity resulting from vaccination; may be long-lasting, Injection of Ag (vaccination) - we make antobodies, Immunity acquired by the transfer of antigens into an organism via a vaccine.
Naïve lymphocyte pool
immunocompetent T cells that have yet to encounter foreign antigens
Margination
increase in adhesion
gamma interferon
increases phagocytosis and has anti-tumor activity
cytokines
interleukins, tumor necrosis factor, colony stimulating factor, chemokines
humoral immunity
involves B cells and the production of antibodies
Cellular immunity
involves t cells (t lymphocytes) to attack foreign organisms as well as abnormal body cells rather than using antibodies. T cells mature in the thymus Effective mostly against intracellular bacteria, virus, and fungi
transferrin
iron is transported in plasma to cells via:
cell-mediated immunity
is modulated by T cells
Skin (stratum corneum)
is the tough outer layer composed of epithelial cells that are cemented together & impregnated with keratin
How does a fever help an infection
it slows growth and increases the immune response
Active Immunization
long lasting immunity natural- body encounters Ag Artificial- Ag as a vaccine
low grade fever: 37.7 - 38.3°C or 100 - 101°F high fever: 40.0 - 41.4°C or 104 - 106°F
low grade fever: high fever:
The contraction of skeletal muscle
lymph is moved through the body by:
secondary lymphoid organ
lymph node, spleen, tonsil, or lymphocyte accumulation in gastrointestinal, respiratory, urinary, or reproductive tract; site of stimulation of lymphocyte response
bone marrow stem cells produce
lymphocytes
T & B Cells
lymphocytes develop into:
T-cells
lymphocytes originating in the thymus gland that are responsible for Cell-Mediated Immunity
humoral immunity
lymphocytes produce antibodies called B cells that act against foreign substances
CTLs
lyse or induce apoptosis in the target cell
NK cells
lyse virus infected cells, tumor cells and parasites; they kill cells that do not express normal "self" MHC class 1 antigens
Antigen Presenting Cells
macrophages, B cells, dendritic cells
Neutrophil
main white blood cell, contains lysosomes and reacts early during inflammation
clonal selection
make millions of copies of B cells
siderophores
many bacteria possess __________ that can have a greater affinity for iron than transferrin
anamnestic response
memory cells activate response to antigen
Chemotaxis
migration of cells in response to a specific chemical stimulus at the site of injury & remain there to perform general & specific immune functions
Cytokines
molecules that signal immune cells to do certain things
macrophages & dendritic cells
monocytes develop into _______ & __________
Serum IgA antibodies
monomers
IgG
most common found in blood and can enter tissues can cross the placenta: confers passive immunity to fetus binds antigens very strongly
phagocytosis
most common method of destroying non-self proteins:
Memory Component
much stronger immune response upon reexposure long term immunity
fc region
name for stem of Y on antibody
types of acquired immunity
naturally acquired active (from disease), naturally acquired passive (across placenta), artificially acquired active (vaccination), artificially acquired passive (inject antibody-rich serum or IGG)
IG actions
neutralize toxin; coating causing opsonization; activation of cytolysis cascade: antibody mediated cell specificity
Innate immunity
non-specific defenses since birth
Primary response
occurs after initial contact with Ag (antigens)
Primary Response
occurs after initial contact with the antigen
Secondary (memory or anamnestic) response
occurs after second exposure, causing memory cells to quickly transform into plasma cells that produce antibodies
imprecise joining
occurs at all V-D-J jxns during recombination; different reading frames produced and different Ag binding pocket
IgD antibodies
on B cells; they may help delete B cells that produce antibodies against self
fc region
on an antibody molecule, what is the term for the stem region?
one antibody
one antigenic determinant
IGD
only on B cell surfaces
Epitope
part of an antigen recognized by immune system
opsonization
pathogen is coated with antibodies, enhancing phagocytosis
burns
patients with severe _______ are very susceptible to all kinds of infections
IgM
pentamer stay in blood aggregate antigens 1st produced
IGM
pentamer structure from binding five together antibodies
Monocytes
phagocytic and can mature into macrophages
What happens during opsonization?
phagocytic cells have receptors for the Fc region of IgG molecules, making it easier for the phagocyte to engulf antibody-coated antigens
What is the difference between serum and plasma
plasma contains clotting factors
Basophils
plays a role in allergic reaction
Phagocytosis
process in which phagocytes engulf and digest microorganisms and cellular debris
T cells recognize antigens
processed by antigen-presenting cells and in association with MHC on an APC
Exogenous pyrogens. Ex: viruses, bacteria, protozoans, fungi, endotoxin, blood, blood products, vaccines, or injectable solutions
products of infectious agents that cause fever. Ex?
Endogenous pyrogens. IL-1 and TNF
products of monocytes, neutrophils, an macrophages that cause fever. What two particular chemicals?
Qualities of effective vaccines
protect against exposure to pathogens; low level of adverse side effects or toxicity; stimulate both antibody and cell-mediated response; produce memory; not require numerous doses or boosters; inexpensive; have a long shelf life; easy to administer
Alpha interferon (IFN) and IFN beta
protect cells against viruses
Specific Component
protects against one pathogen only exception when two are closely related
Antibody
protein that helps destroy pathogens (made in response to an antigen). a protein produced by B cells in response to an antigen and is capable of combining specifically with that antigen
secondary response
rapid antibody production that occurs following re-exposure to the antigen. IgG is the predominant antibody produced during this.
T cell components
receptor antibodies on surface to find antigens, most important are CD4 and CD8
T cell receptors
recognize antigens
T-cell receptors on T cells
recognize antigens
PAMP's
red flags of pathogens
thymic selection
removes T cells that don't recognize MHC-self molecules
Clonal Expansion
repeated cell division generates population of copied antibodies
primary response
response of IGM within 1 week, IGM within 2 weeks, then declines is called what?
T cells
responsible for cellular immunity
Major Histocompatability Complex (MHC)
responsible for lymphocyte recognition and "antigen presentation". The MHC molecules control the immune response through recognition of "self" and "non-self" and, consequently, serve as targets in transplantation rejection.
Artificial Adaptive Immunity
results from immunization by a vaccine
subsequent contact with the same antigen
results in a very high antibody titer and is called secondary or memory response; antibodies are primarily IgG
immunological memory
second exposure, anamnestic or secondary response
antiserum
serum containing antibodies
complement system
serum proteins involved in cytolysis
Complement
serum proteins that bind to antibodies in an Ag-Ab reaction (causes cells to lysis)
IGA
10-15% of IGs, in secretions, dimer, two monomers held by J chain
Compliment
26 proteins; Punches holes into invading cells
Secondary Response
2nd encounter high levels of Ab 1-2 days memory cells replenished
-perspiring -lowering the metabolic rate -dilating the blood vessels of the skin
3 ways the body cools when fever lowers:
Classes of Antibodies
5 classes which are based on the constant region of the antibody -IgM - Primary response, T-independent antigens -IgG - secondary response -IgA - mucosal immunity - tears, mucus, saliva, Br. Milk -IgD - Not Well Understood -IgE - Allergic Reactions
pathogen-associated molecular patterns (PAMPs) -Not present in mammals
signal molecules found on microbial surfaces recognized by phagocytes & other defensive cells; 'red flags': -Not present in ___________
IGG
80% of circulating antibodies
T cell receptors
A T cell has ~500,000 copies of this on the surface of its cytoplasmic membrane; are generated by the random combination of DNA in the related gene regions; contain only one antigen-binding site.
Sebum
A chemical barrier that lubricates the skin
Lymph
A colorless, watery liquid that arises from the fluid that has leaked out of blood vessels into the surrounding intracellular space; contains wastes (degraded proteins and toxins) and is pumped; through a one-way system, to the heart where it returns to the circulatory system.
Cardiovascular disease
A disease caused by chronic inflammation:
1. surveillance of the body 2. recognition of foreign material 3. destruction of entities deemed to be foreign
A healthy, functioning immune system is responsible for (3):
Spleen
A lymphatic organ, similar in structure to the lymph nodes, that performs the function of filtering or screening of bacteria, viruses and toxins from blood (as opposed to lymph in the case of the lymph nodes). Blood components, such as iron and platelets, are often stored here.
Natural Killer Cells
A type of white blood cell that can kill tumor cells and virus-infected cells; an important component of innate immunity.
Subunit vaccines
A vaccine based on a selected component of a microorganism; the antigens used in these vaccines may be taken from culture or synthesized chemically.
Antibody Mediated Response
AKA: Humoral Response Ab specifically bind to and inactivate foreign particles
t cell activation
APCs (most often a dendritic cell) migrate to lymph nodes and other lymphoid tissues to present their antigens to T cells T cell activation is a two-step process: 1. Antigen binding 2. Co-stimulation
Complement Activation
Ab binds bacteria and starts complement pathway(MAC Attack)
Neutralization
Ab binds to Ag and inactivates it prevents it from adsorbing to host cells
B lymphocytes
Ab producing cells, involved in humoral response. Specific lymph cells arising from and maturing in the red bone marrow. Following maturation these lymphocytes are generally found in the spleen, lymph nodes, red bone marrow, and Peyer's patches. Few circulate in the blood at a given time. Their major function is the secretion of antibodies.
Natural Immunity
Acquired through the normal life experiences of a human and is not induced through medical means
B Cell Activation
Activated B cells: These cell proliferate because their B-cell receptors are bound to antigen X and the cells have received required signals from TH cells.
Memory T cells
Activated T cells that persist for months or years in lymphoid tissues.
Functions of Antibodies
Agglutination Neutralization Complement Activation Opsonization Ab Dependent Cytotoxicity
Antigen-Antibody Binding
Agglutination Opsonization Activation of complement Antibody-dependent cell-mediated cytotoxicity Neutralization
True
All complement pathways have the same end result. T or F?
What cells can function as antigen presenting cells? What is immunosurveillance? What leukocytes perform immunosurveillance?
All nucleated cells can function as antigen presenting cells. T cells perform immunosurveillance. Cytotoxic T cells survey antigen presented by MHC 1 and Helper T cells survey antigen presented by MHC 2
Cellular Immunity
Also called cell-mediated immunity. This process results in the production of T cells and natural killer, NK, cells that directly attach to foreign cells. This immune response fights invasion by viruses, bacteria, fungi, and cancer.
Antigenic determinants
Also known as epitopes; the three-dimensional shape of a region of an antigen that is recognized by the immune system.
Extra Cellular Killing
some microbes are larger than the immune cells so they cannot be digested (parasites/flukes)
Lacteals
special lymphatic vessels stationed in each intestinal villus
Histiocytes
specialized macrophages that live in a certain tissue & remain there during their lifespan:
Endogenous antigens
An antigen produced by microbes that multiply inside the cells of the body.
Exogenous antigens
An antigen produced by microorganisms that multiply outside the cells of the body.
t-independent antigens
An antigen that will stimulate the formation of antibodies without the assistance of T helper cells.
t cell receptors
An antigen-binding protein, located on the surfaces of CTLs (cytotoxic or killer T cells).
What is an antigenic determinant (epitope)? What are the characteristics of epitopes?
An epitope is the region of the Antibody that the adaptive immune system recognizes. Some epitopes are 10 amino acids long, others are 3-D shapes that stick out in a molecule.
Pre-Clinical Trials
Animal trials often including mice, rabbits, etc.; very few vaccines reach this point
Anatomical barriers
Another name for physical barriers
Proteins
Antibodies are what type of cell?
Passive Natural Immunity
Antibodies circulating in the mother's bloodstream pass to the fetus through the placenta; can also get it from mother's milk
Adaptive immunity
specific response to a specific microbe, acquired naturally or artificially, acquired actively or passively, specific and have memory. Immunity, resistance to a specific pathogen (specific antibody and lymphocyte response to an antigen) Third line of defense Humoral response - antibody mediated (B cells) Cell-mediated (T cells)
B Cell Effector action
Antibodies: These neutralize the invader and tag it for destruction.
IgA
Antibody associated with body secretions
IgE
Antibody involved in response to parasitic infections and allergies
Two AI Responses
Antibody mediated responses Cell Mediated Response
Immunoglobulin D
Antibody that is not found in all mammals and its function or importance is currently not very well understood.
Immunological Memory
Antibody titer Primary response occurs Secondary (memory or anamnestic) response
What happens during complement system activation?
Antigen-antibody complexes can trigger the classical pathway of complement system activation.
T Cells
stem cells develop thylmus - then go to thymus - turn into T cells - then migrate to Lymphoid tissue (they trigger other cells to start fighting)
(Activation of) B cells
stimulated to rapidly divide by the binding of one specific antigen to its specific antibody on the surface of the cell; process called "clonal selection", usually requires help of "helper t cells" and "major histocompatibility complex" proteins on the surface of the b cell
affinity
strength of antibody
Autoantigens
Antigens on the surface of normal body cells.
t-dependent antigens
Antigens that can stimulate antibody production only with help from T helper cells
Pyrogens
substances that reset the hypothalamic thermostat to a higher setting and cause fever:
T regulatory cells
suppress T cells against self
Passive Immunization
temporary immunity Natural- mother to infant Artificial- Ab injected(for life threatening situations snakebite)
cytokines
term for communication molecules used by T cells to coordinate responses
For T-dependent antigens
the B cell's immunoglobulins combine with an antigen, and the antigen fragments combined with MHC class 2 activate Th and Th2 cells activate a B cell
Sugar and proteins
Antimicrobial peptides are triggered by _______ & ________ on microbe surface.
expansion
the act, process, or result of enlarging
What are the characteristics of antigens? Which antigens stimulate a strong adaptive immune response and which do not?
Any molecule that reacts specifically with an antibody. Proteins are good antigens. Lipids and Nucleic Acids are not good antigens.
Characteristics of B Cells
Arise and Mature in Red bone Marrow, Found Primarily in Spleen, Lymph Nodes, and MALT, Major Function is the secretion of anitbodies.
T lymphocytes
Arise from stem cells in the red bone marrow, but undergo maturation in the thymus. Following maturation, these cells circulate through the blood and lymph, migrating to the lymph nodes, spleen, and Peyer's patches (as well as accounting for 70-85% of all lymphocytes in the blood); part of the body's cell-mediated immune response since these cells act directly against antigens.
decreases & the thermostat is reset to 37 degrees C
As the infection becomes under control & fewer active phagocytes are involved, the level of pryogens:
What are the phases of Phagocytosis
Attract Bind Engulf Digest
Complementary
B Cell Antigen Binding Sites are what to epitopes?
BCR
B Cell Receptor
Lymphocyte receptors
B and T cells have membrane bound receptors that recognize specific antigen B Cell Receptor (BCR) - specific antibody B cell is programmed to make T Cell Receptor (TCR) - Doesn't recognize free antigen, must be presented by an Antigen Presenting Cell
Clonal Selection
B cell bound to Ag is activated and divides
Clonal Expansion
B cell differentiates into plasma cells(Ab cells) and memory cells memory cell are long living and if they encounter the antigen again will initiate a quick response
T-Dependent Antigens
B cell requires confirmation from TH cell to be activated
For T-independent antigens
B cells are selected by free antigens
Clonal Selection
B cells circulate until they find antigens present to MHC MHC says its dangerous Th cells activate B cells- which undergo clonal expansion
Primary Response
B cells produce low levels of Ab 7-14 days IgM first, then IgG and IgA memory built
Antigen Presenting Cells (APCs)
B cells, Dendritic Cells, macrophages, ingests and displays fragments of antigen on surface
APCs include
B cells, dendritic cells and macrophages
Types of Lymphocytes
B- Lymphocytes T-Lymphocytes
Superantigens
Bacterial toxins that stimulate T cells resulting in overwhelming release of cytokines and cell death (TSS)
Neutralization
Blocks adhesion(antigens from attaching) to mucosa and attachment of toxin
37°C (98.6°F); by the hypothalamus
Body temperature is maintained at ___°C (98.6°F) by the:
Primary Lymphoid Organs
Bone marrow and thymus
IgA
the class of immunoglobulin having alpha heavy chains; these antibodies are those in dimeric form present in mucosal secretions; present in the blood in monomeric form
IgD
the class of immunoglobulin having delta heavy chains; appears as surface immunoglobulin on mature naive B cells but its function is unknown
Serum
the clear fluid from clotted blood
opsonization
the coating of an antigen with antibody and it enhances phagocytosis of the antigen
Helper T Cells
CD4 - Multiply and develop into cells that activate B cells and macrophages - Stimulate other T cells; orchestrate immune response - Recognize MHC class II -Activates macrophages, B cells, and Cytotoxic T cells -Antigen source - Exogenous - produced outside of target cell
Cytotoxic T Cells
CD8 -Proliferate and differentiate to destroy infected or cancerous "self" cells - Recognize MHC class I -Induces cell to undergo Apoptosis -Antigen source - Endogenous - produced w/in target cell
Cytotoxic T Cells
CD8+ T cells recognize host cells presenting "non-self" antigens, they bind to the infected cell and kill it
heat given off by the increased flow of blood
Calor caused by:
Lymph cells
Cell that arise from stem cells located in the red bone marrow. One of the most important is the lymphocyte, a type of small agranulocyte.
T-lymphocyte response:
Cell-mediated immunity
Antibody-secreting plasma cells
Cells that secrete antibodies that are specific to the antigens found in the epitope-MHCII complex.
innate immunity
the individual's genetically predetermined resistance to certain diseases
primary response
the initial immune response to an antigen, which appears after a lag of several days
Siderophores and Lactoferrin
Chemical tug of war for iron is between what two chemicals?
Where do T-Cells go?
Circulate in lymph and blood and migrate to lymph nodes, spleen and Peyer's patches
Opsonization
Coating antigen with antibody enhances phagocytosis
Antibody-dependent cell-mediated cytotoxicity
Coats forgin cells with antibodies. non-specific immune cells then destroy the foreign cell from the outside. This is used for organisms that are too large for phagocytic cells to ingest. Cause destruction by macrophages, and NK cells
Complications of Vaccines
Common reactions: local reactions at injection site, fever, and allergies; Rare reactions: Panencephalitis (measles vaccine), back mutation to a virulent strain (polio vaccine), disease due to contamination with dangerous viruses or chemicals, neurological effects of unknown cause (Pertussis and swine flu vaccines), allergic reactions to the medium (egg or tissue culture)
26
Complement consists of Consists of how many blood proteins that work to destroy bacteria & certain viruses?
Cascade reaction
Complement sequential physiological response:
IgG
the most common antibodies. passable through the placenta. provides passive immunity. aka gamma globulin
IgG antibodies
the most prevalent in serum; provide naturally acquired passive immunity; neutralize bacterial toxins, participate in complement fixation and enhance phagocytosis
primary response
the response of the body to the first contact with an antigen; characterized by the appearance of IgM followed by IgG
Antibody Structure
Constant or Fc Region Variable or Fab Region Two copies of heavy chain and two of light Amino Acids fold into characteristic domains Light chains have two Heavy Chains have four Fork of Y is flexible hinge region
Regulatory T-cells:
Control the T-cell response
Immunology
the study of all features of the body's 2nd & 3rd lines of defense
Monocytes Macrophages Lymphocytes Fibroblasts Mast cells Platelets Endothelial cells
Cytokines are produced by (7):
What type of T cells survey for antigens presented by MHC 1? MHC 2? What molecules on the surfaces of these T cells are involved in the recognition of antigens presented by MHC 1 and MHC 2?
Cytotoxic T cells survey for antigens presented by MHC 1. CD8 is on the surfaces of the T cells. Helper T cells survey for antigens presented by MHC 2. CD4 is on the surfaces of the T cells.
Natural killer cells
Cytotoxic lymphocyte that lacks specificity for antigens and eliminates cells similar to Tc cells
Three Types of T-Cells
Cytotoxic, Helper, and Regulatory
How are T cells activated by dendritic cells?
Dendritic cells that have engulfed microbial fragments produce co-stimulatory molecules. Naïve T cells that recognize antigen presented by a dendritic cell that expressed co-stimulatory molecules may become activated, allowing them to proliferate and develop their effector functions.
Natural Killer Cells
Descend from lymphoid stem cells - Lack antigen receptors • Attach to antibody-coated cells (recognize Fc portion of antibodies) Actions augment adaptive immune response - Important in process of ADCC NK cells recognize destroyed host cells with no MHC class I surface molecules •Some viruses cause host cell to present fake MHCs which are not recognized by NK cells
HIV
the virus that causes acquired immune deficiency syndrome (AIDS) as it passes through phases 1-3 it continues to kill T cells (required to call other cells to come an fight the infection) AIDS is the final stage
Cytotoxic T-cells:
Destroy infected host cells and foreign cells
IgA
Dimer 10-15% of serum antibodies In secretions, tears, mucus, colostrum, lymph Mucosal protection Half-life = 6 days
Peyer's patches
Discrete portions of mucous-associated lymphoid tissue located in the small intestine
TCR's
Do not recognize epitopes directly, but bind them to T-Cells
pain caused by stimulation of nerve endings
Dolor caused by:
Roles of lymphatic vessels
Drain excess fluid from tissue Carry leukocytes, cell debris and microbes
Plasma; exudate
During inflammation, ______ from blood vessels leaks into the tissues & forms:
How does the lymphatic system function in detecting foreign antigen?
Each lymphocyte recognizes one or a few antigens, so in order for the body to mount an effective response the lymphocyte must encounter the appropriate antigen.
Resident microbiome
Each person's ____________ trains host defenses to eliminate pathogens.
Humoral Immunity
Eliminates extracellular pathogens • Mediated by B cells • Develops in bone marrow • B cells may be triggered to proliferate into plasma cells • Some B cells produce memory cells
Cellular Mediated Immunity
Eliminates intracellular pathogens • Mediated by T cells • Matures in thymus • Divided into 2 subsets (Cytotoxic T cells and Helper T cells)
Clonal deletion
Elimination of T and B cells that react with self antigens
What is an endogenous antigen? How are endogenous antigens presented? What cells can present endogenous antigens? What molecules present endogenous antigens?
Endogenous antigens originate in the cytoplasm. All cells can present endogenous antigens. MHC 1 presents endogenous antigens.
IgD
Exact function of this antibody is not known
What is an exogenous antigen? How are exogenous antigens presented? What cells can present exogenous antigens? What molecules present exogenous antigens?
Exogenous antigens originate outside of the cell. B cells, Macrophages, dendritic cells, and monocytes can present. MHC 2 molecule presents exogenous antigens.
Macrophages
they are phagocytes that destroy bacteria by eating them
How do microbiota help
they compete for nutrients by producing substances that are harmful to pathogens
Iron released by macrophages
Fever Impedes nutrition of bacteria by reducing the availability of:
Tissue repair
Final stage - tissues replace dead or damaged cells
IgM
First Antibody produced
Primary Response
First response to particular antigen
T cells mature in the
thymus
IGM within 1 week, IGG within 2 weeks
time between exposure to antigen and production of antibodies
MHC Class I
Found on all nucleated cells Bind endogenous antigen
MHC Class II
Found only on APCs (B cells, Dendritic cells, and macrophages) Bind exogenous antigen
1. Interferon 2. Complement 3. Iron-binding proteins 4. Antimicrobial peptides
Four antimicrobial proteins:
1. Inhibits multiplication of temperature-sensitive microorganisms 2. Impedes nutrition of bacteria 3. Increases metabolism 4. Speeds up hematopoiesis, phagocytosis, specific immune reactions & tissue repair
Four benefits of fever:
1. the reticuloendothelial system (RES) 2. the extracellular fluid (ECF): spaces surrounding tissue cells 3. the bloodstream 4. the lymphatic system
Four body compartments that participate in immune function:
1. alveolar (lung) macrophages 2. Kupffer cells in the liver 3. dendritic cells in the skin 4. macrophages in spleen, lymph nodes, bone marrow, bone & brain
Four examples of monocytes/macrophages
1. phagocytosis 2. inflammation 3. fever 4. antimicrobial proteins
Four factors of the second line of defense:
neutrophils monocytes tissue macrophages dendritic cells
Four types of phagocytes
IgD
Function unknown
What are the functions associated with antibodies?
Functions are neutralization, opsonization, complement system activation, immobilization and prevention of adherence, cross-linking, and antibody-dependent cellular cytotoxicity (ADCC)
-the appendix -Lacteals -Peyer's patches
GALT includes:
Lysosomes
Granules that carry digestive enzymes & other chemicals that degrade phagocytosed material:
T Cell Characteristics
Have multiple copies of T Cell receptors, which do not react with free antigens Antigen must be presented by Major histocompatability complex molecules
skin lungs liver lymph nodes spleen bone marrow
Heavily endowed with macrophages waiting to attack microbes as they arrive in the (6):
T-Lymphocytes
Helper T-cells Cytotoxic T-cells-destroy abnormal body cells cell mediated response
five types of T cells
Helper, cytotoxic, delayed hypersensitivity, suppressor, memory
1. Are the precursors of new blood cells 2. Are maintained in the bone marrow 3. Proliferate & differentiate into RBC, WBC & platelet
Hematopoietic stem cells (3 things):
Bacterial infection
High neutrophil count is a sign of a:
cytoplasmic membrane receptors & Opsonins such as complement & antibody
How does a phagocyte 'know' it is in contact with a pathogen instead of another body cell?
Iron
Humans & bacteria require ____ for cytochromes in the electron transport chain & as cofactors for enzymes
Natural Killer T cells
Hybrid cells that are both killer cell and T cell; it has T cell receptors for antigen and the ability to release large amounts of cytokines
Disorders Associated With Immune System
Hypersensitivity Autoimmune diseases B-cell deficiencies T-cell deficiencies (7%)
five antibody types
IGG, IGA, IGD, IGE, IGM
Role of Th cells in B cell activation
If TH cell encounters B cell bearing peptide: MHC class II complex TH cell responds by producing cytokines B cell is activated in response to cytokine stimulation B cell proliferates and undergoes class switching Also drive formation of B memory cells
What causes inflammation
trauma from infection tissue injury due to physical and chemical agents specific immune reactions