Adaptive Immunity

Question 1

What are some key differences between active and passive immunity? Please give examples.

Answer 1

Self created vs non self created
strength of immunity

Question 2

Define an antigen.

Answer 2

Usually a foriegn substance that activates immune response. Usually made of proteins, and are parts of a virus, bacteria, or helminth.

Question 3

Describe the process by which B-lymphocytes are activated if the antigen is T-independent.

Answer 3

B cell binds to t-independent at multiple spots and is activated directly and proliferates into mem B and plasma.

Question 4

Define epitope and hapten.

Answer 4

hapten: a small antigen that must bind to a carrier molecule to bind to an antibody. Allergens.
epitope- antigenic determinant, portion of antigen that is binding to the antibody.

Question 5

Which type of cytokine is a key co-stimulator of T cell activation?

Answer 5

interleukins

Question 6

Describe the process that results in an antigen-presenting cell. Which cells can act as APC’s?

Answer 6

Cells are dendritic, macrophages, and activated B cells.

Question 7

antibody titer

Answer 7

measurement of the amount of antibodies present after exposure to an antigen

Question 8

Describe the 5 classes of antibodies (MADGE). For each describe its structure, function and relative percentage in the blood (most to least).

Answer 8

Most to least
IgG- crosses placenta, immune response
IgA- in secretions
IgM- first to be secreted by plasma cells
IgE- allergic response and attached to basophils
IgD- unknow use, possibly receptor

Question 9

What does it mean for a B or T cell to immunocompetent? What do they acquire?

Answer 9

They have their unique receptors.

Question 10

Distinguish between exogenous and endogenous antigen as well as autoantigens.

Answer 10

Exogenous-outside of host cell
Endogenous- inside host cell (virus)
autoantigen- not foreign normal self tags on cells.

Question 11

How do activated cytotoxic T cells kill their targets?

Answer 11

perforin-granzyme cytotoxic pathway- perforins poke holes in cells and granzymes destroy them with enzymes
CD95 cytotoxic pathway- CD95 glycoprotein present on most cells and binds to CD95L receptor on Tc cells. Activates enzymes that cause cell death

Question 12

helper T cells

Answer 12

Director of the immune response and stimulate cytotoxic t cells and b cells.

Question 13

opsonization

Answer 13

coating a microbe with antibodies to enhance phagocytosis

Question 14

neutralization

Answer 14

cages off antigen and prevents from damaging cells

Question 15

memory T cells

Answer 15

clones of the original Th cell that remember an antigen and create a stronger and longer immune response the second time

Question 16

How does the production of antibody in response to a secondary exposure to an antigen compare to the primary response?

Answer 16

Secondary response happens faster, with more antibodies, and lasts a longer time.

Question 17

Describe how T cells achieve self-tolerance and where

Answer 17

Happens in thymus
Positive selection: cells that recognize MHC are kept
Negative selection: cells that do not recognize autoantigens are kept

Question 18

How are T-dependent and T-independent antigens different? Which cells can be activated by T-independent antigens?

Answer 18

T-dependent antigens require a Th cell response to activate Tc and B cells.
T-independent antigens can activate B cells independently.

Question 19

Which cells play a role in adaptive immunity?

Answer 19

B+T lymphocytes

Question 20

Briefly describe the structures of the lymphatic system. Which structures are primary structures and which are secondary structures.

Answer 20

Primary: Red bone marrow and thymus
Secondary: lymph nodes, MALT, spleen

Question 21

How is it that we develop a memory for an antigen? What cells and cell products provide this memory?

Answer 21

Memory T and B cells

Question 22

Describe some characteristics of adaptive immunity.

Answer 22

specificity, clonality, self-tolerance, and memory

Question 23

Distinguish between MHC-I and MHC-II.

Answer 23

MHC 1- on all nucleated cells
MHC 2- only on antigen-presenting cells

Question 24

List and describe the four ways in which immunity is acquired.

Answer 24

artificially acquired active immunity- vaccine
artificially acquired passive immunity- immunotherapy
naturally acquired active immunity- got sick
naturally acquired passive immunity- mother-child

Question 25

Distinguish between exogenous and endogenous antigen processing.

Answer 25

Exogenous- take in antigen from outside the cell and process. Cells phagocytize antigen, digest anitgen with lysosome, vesicles with MHC 2 merge with phagolysosome and epitopes bind to MHC 2 receptors, MHC 2 vesicle merges with cell membrane to present epitope.
Endogenous- processed antigen binds to MHC 1 receptor on endoplasmic reticulum. MHC-1 and epitope complex is packaged in golgi body before displaying on the plasma membrane.

Question 26

cytotoxic T cells

Answer 26

directly kill infected or cancerous cells

Question 27

Describe how B cells achieve self-tolerance (aka clonal deletion of B cells.)

Answer 27

B cells that bind with autoantigens are lysed.

Question 28

antibody-dependent cellular cytotoxicity

Answer 28

Similar to opsonization, the coating of antibodies attracts NK cells that destroy the cell. Often happens on worms.

Question 29

Describe the function of the major histocompatibility complex.

Answer 29

To present epitopes to B and T lymphocytes.

Question 30

Describe the general structure of antibodies. What are antibodies made of?

Answer 30

Antibodies are made of proteins. Contain two heavy chains of amino acids and two light chains, jointed by disulfide bonds at the hinge.
Constant region- the same as all other antibodies in it’s class
Variable region- antigen-specific

Question 31

suppressor T cells

Answer 31

a special type of Th or Tc cell, that has an inhibitory factor that turns off an immune response.

Question 32

Distinguish between the roles that B and T cells play in the adaptive immune response.

Answer 32

T related to cell-mediated immunity
B related to humoral immunity

Question 33

Give an overview of the humoral immune response.

Answer 33

antibody-mediated immunity
B cells differentiate into plasma cells and memory B cells
Plasma cells secrete antibodies

Question 34

Describe the process by which B-lymphocytes are activated if the antigen is T-dependent.

Answer 34

Th cell is activated after receiving epitope from APC
Th cell changes to a Th2 through interleukin
B cells that have the appropriate MHC-II epitope complex will bind to Th2 cell.
Interleukin and binding activates B cell and causes proliferation

Question 35

agglutination

Answer 35

clumping of cells to increase phagocytosis and prevent invaders from sticking to cells

Question 36

Describe how cytotoxic T cells are activated. Which cells play a role in assisting with the activation?

Answer 36

Assisted by Th cell
APC presents processed antigen to on MHC1 and binds to Tc cell.
Th cell binds to MHC2 on APC and secretes interleukins which transforms it to Th1.
Th1 secretes interleukin which activate Tc cell.
Tc cells become self stimulatory and proliferate.