ELE_IVC Adaptive Immune Response

adaptive immune (specific defense) system

This system protects against infectious agents and abnormal body cells by amplifying the inflammatory response and activating the complement system.

True.

The adaptive immune system must be primed by initial exposure to specific foreign substance which takes time.

T or F?

specific

This adaptive immune defense characteristic recognizes and targets specific antigens.

systemic

This adaptive immune defense characteristic refers to not being restricted to the initial site.

known

Adaptive immune defenses have memory therefore they have stronger attacks to ______ antigens.

humoral and cellular immunity

What are the 2 main mechanisms of immunity in the adaptive immune system?

humoral immunity

A type of specific immunity produced by B cells that produce antibodies that circulate in body fluids such as plasma.

cellular immunity

A type of specific immunity that results in the production of T cells and natural killer, NK, cells that directly attach to foreign cells.

antigens

These are large, complex substances that can mobilize adaptive defenses and provoke an immune response.

False. Not normally found in the human body.

Antigens are normally found in the human body.

T or F?

complete antigens

This type of antigens are macromolecular and have two important functional properties: immunogenicity and reactivity.

e.g. foreign protein, polysaccharides, lipids, and nucleic acids

immunogenicity

This important functional characteristic of complete antigens refers to the antigen's ability to stimulate lymphocyte proliferation.

reactivity

This important functional characteristic of complete antigens refers to the antigen's ability to react with lymphocytes.

incomplete antigens (haptens)

This type of antigens are small molecules that are not immunogenic themselves; only half-immunogenic since its immunogenicity depends whether it's attached a full particle (e.g. protein, carbohydrate, etc.)

e.g. poison ivy, animal dander, detergents, and cosmetics

antigenic determinants

Only certain parts of an antigen called __________ are immunogenic; antibodies and lymphocyte receptor bind to them as enzyme binds substrate.

self-antigens

These are protein molecules on the surface of cells which are not antigenic to self but antigenic to others in transfusions or grafts.

MHC glycoproteins

This is an example of a self-antigen wherein they're unique to every individual; has a receptor-like groove holding a self- or foreign antigen.

red bone marrow

Both B and T lymphocyte precursors originate in the?

thymus

Lymphocyte precursors destined to become T cells migrate (in blood) to the _______ and mature there.

bone marrow

Lymphocyte precursors destined to become T cells stay in the _______ and mature there.

immunocompetence and self-tolerance

During maturation, lymphocytes develop these 2 characteristics namely:

immunocompetence

This lymphocyte characteristic developed during maturation refers to the ability of the lymphocyte to recognize and bind an antigen.

self-tolerance

This lymphocyte characteristic developed during maturation refers to a lymphocyte's unresponsiveness to self-antigens.

True.

Lymphocytes that are immunocompetent but are still naive can leave the thymus and bone marrow to seed the secondary lymphoid organs and circulate through blood/lymph.

T or F?

activated

When a lymphocyte's antigen receptors bind its antigen, that lymphocyte can be ___________.

effector and memory cells

Activated lymphocytes proliferate and differentiate into _____ and _____ cells which circulate continuously in the blood and lymph through the spleen and lymph nodes.

True.

In positive selection, T cells must recognize self-MHCs but in negative selection, T cells must not recognize self-antigens. Failure to do either results in apoptosis.

T or F?

B cells

These are lymphocytes that mature in the red bone marrow; undergoes positive selection if antigen receptors are successfully made.

self-reactive

B cells are ______ and are eliminated by apoptosis (clonal deletion).

clonal selection

This theory refers to a naive lymphocyte's first encounter with an antigen, selected for further development. If the correct signals are present, the lymphocyte will complete its differentiation.

extracellular pathogens

What are the primary targets of humoral immunity (B-cell mediated)?

intracellular pathogens

What are the primary targets of cellular immunity (T-cell mediated)?

plasma cells

Which cells are effector cells in humoral immunity?

cytotoxic T (T_c)

helper T (T_h)

regulatory T *T_reg)

Which 3 cells are effector cells in cellular immunity?

False. Both.

Only humoral immunity forms memory cells.

T or F?

primary immune response

This immune response involves cell proliferation and differentiation upon first antigen exposure.

3-6 days

How long is the lag period of the primary immune response?

secondary immune response

This immune response refers to the re-exposure to the same antigen which gives faster, more prolonged and effective response.

hours

In the secondary immune response, sensitized memory cells respond within _________.

2-3 days

In the secondary immune response, antibody levels peak in __-__ days at much higher levels.

naturally acquired active humoral immunity

This type of active humoral immunity refers to the response to bacterial or viral infection.

artificially acquired active humoral immunity

This type of active humoral immunity refers to the response to vaccine of dead or attenuated pathogens.

vaccines

These are therapeutics composed mostly of dead or attenuated pathogens that induce symptoms of the primary response when administered; provides antigenic determinants that are immunogenic and reactive.

passive humoral immunity

This type of humoral immunity involves ready-made antibodies introduced into the body wherein B cells are not challenged by antigens.

naturally acquired passive humoral immunity

This type of passive humoral immunity involves antibodies delivered to the fetus via placenta or to the infant through milk.

artificially acquired passive humoral immunity

This type of passive humoral immunity involves gaining antibodies through injection of serum such as gamma globulin.

True.

B cells are stimulated in active humoral immunity while in passive, they are not stimulated.

T or F?

False. Other way around.

Active humoral immunity doesn't rely on immunological memory while passive humoral immunity does.

T or F?

immunoglobulins

These are protein molecules that form the gamma globulin portion of blood, secreted by plasma cells.

Capable of binding specifically with antigens detected by B cells.

IgM

This immunoglobulin is a pentamer; first Ig secreted by plasma cells during the immune response.

Readily fixes and activates the complement system.

IgA

This immunoglobulin is a dimer; found in body secretions such as saliva, sweat, intestinal juice, and milk.

Helps stop pathogens from attaching to epithelial cell surfaces (including mucous membranes and the epidermis).

IgD

This immunoglobulin is a monomer; found on the B cell surface and functions as a B cell antigen receptor like IgM.

IgG

This immunoglobulin is the most abundant antibody in plasma (75-85% circulating antibodies); main antibody of both secondary and late primary responses.

Readily fixes and activates the complement system; important in conferring passive immunity from mom to fetus.

IgE

This immunoglobulin has a stem end that binds to mast cells or basophils, releasing histamine and other chemicals that mediate inflammation and allergic reactions.

1. neutralization

2. agglutination

3. precipitation

Antigen-antibody complexes are inactivated by (3):

complement system

Antigen-antibody complexes fixes and activates which system?

phagocytosis and inflammation

The 3 inactivation mechanisms of antigen-antibody complexes enhance (2):

cell lysis

The fixation and activation of the complement system by antigen-antibody complexes leads to?

week

Primary T cell responses peak within a?

7 and 30

T cell apoptosis occurs between day __ and __.

T cells are considered hazards since they produce a large amount of inflammatory cytokines which may cause hyper-, neoplasia.

What is the benefit of T cell apoptosis?

antigen

Effector activity diminishes as amount of _______ declines.

cytokines

These are chemical messengers of the immune system including interferons and interleukins.

IL-1

This interleukin is released by macrophage to co-stimulate bound T cells to release IL-2 and synthesize more IL-2 receptors.

IL-2

This interleukin is a key GF, acting on cells that release it and other T cells; it is co-stimulatory meaning it can stimulate itself and other T cells.

helper T cells

These are T cells that help the immune system by increasing the activity of killer cells and stimulating the suppressor T cells.

Activates both humoral and cellular immunity so without these cells, there is no immune response.

interleukins

When T_H cell aids in humoral immunity, they release ______ as co-stimulatory signals to complete B cell activation.

CD8 cell

When T_H cell aids in cellular immunity, once dendritic cell is stimulated, it can now activate ___ cell with the help of IL-2 secreted by T_H cell.

1. amplify responses of innate immune system

2. activate macrophages to become more potent killers

3. mobilize lymphocytes and macrophages, attract other types of WBCs

3 main functions of helper T cells:

TH1

This T_H cell subset mediates most aspects of cellular immunity.

TH2

This T_H cell subset defends against parasitic worms, mobilize eosinophils, and promotes allergies.

TH17

This T_H cell subset links the adaptive and innate immunity by releasing IL-17; may play a role in autoimmune diseases.

cytotoxic T (T_C) cells

These T cells directly attack and kill other cells; circulate in the blood, lymph, and lymphoid organs in search of body cells displaying antigens they can recognize.

perforins and granzymes

T_C cells secrete molecules called ______ and enzymes called ______ by exocytosis which causes a lethal hit.

1. perforin and granzyme release

2. binding to a membrane receptor to stimulate apoptosis

What are the 2 ways in which T_C cells can induce a lethal hit?

natural killer (NK) cells

These are cells that recognize other signs of abnormality; uses same key mechanisms as T_C cells for killing their target cells (immune surveillance).

True.

T cells respond only to processed fragments of antigens displayed on cell surfaces.

T or F?

antigen presentation

This is vital for naive T cell activation and normal functioning of effector T cells.

Class I MHC proteins

This class of MHC protein is displayed by all cells except RBCs.

Class II MHC proteins

This class of MHC protein is displayed by APCs (dendritic cells, macrophages, B cells)

ER

Where are MHCs synthesized before binding to peptide fragments?

endogenous

Foreign antigens on Class I MHCs are?

exogenous

Foreign antigens on Class II MHCs are?