Ch.17 Adaptive Immunity

Question 1

what are antigens (Ag)?

Answer 1

are molecules that in the body activate lymphocytes

Question 2

what do B cells do?

Answer 2

interact w/antigen via surface immunoglobins i.e, antibodies

Question 3

what do T cells do?

Answer 3

interact w/ antigen via surface antigen receptors

Question 4

how does interaction with antigens with smaller segments occur

Answer 4

epitopes or antigenic determinants

Question 5

what are epitopes that elicit an immune response?

Answer 5

protein, peptide, or complex polysaccharides

Question 6

what are variable regions?

Answer 6

possess variable amino acid sequences and are antigen-binding sites

Question 7

what are the antibody classes of IgG, IgD, and IgE?

Answer 7

monomer forms

Question 8

what are the antibody classes of IgM, and IgA?

Answer 8

are aggerates of 2 or more monomers

Question 9

describe IgA

Answer 9

dimer

found mainly on mucosal surfaces & in secretions

prevents pathogen attachment to surfaces

Question 10

describe IgG

Answer 10

monomer

most abundant in blood and tissue fluids

opsonization

activate complement

neutralize viruses

Question 11

describe IgD

Answer 11

found on B cells & in blood, lymph

Question 12

describe IgM

Answer 12

The circulating type is a pentamer

generally remains in blood vessels

first Ab detected in immune response

effective in aggulation & complement activation

Question 13

describe IgE

Answer 13

found on the surface of mast cells & basophils

cause release of histamines & other chemicals by the cells in the presence of antigen

can attract complement, phagocytic cells

Question 14

what is the humoral immune response most effective?

Answer 14

extracellular pathogens

Question 15

what is the humoral immune response to a microbe?

Answer 15

is a composite of responses to different epitopes by thousands of b cells

Question 16

what do B cells possess?

Answer 16

surface immunoglobins that bind to their specific epitope which activate B Cell

Question 17

what do b cells require

Answer 17

T dependent antigens

T helper cells that interact with each other

Question 18

how do T helper cells bind antigens?

Answer 18

via MHC class II receptors on B cells

Question 19

what is the key to B cell response?

Answer 19

clonal selection

Question 20

what is clonal selection?

Answer 20

the proliferation of B cells that respond to a specific antigen

Question 21

what happens when a B cell contracts its cognate antigen?

Answer 21

it is stimulated to proliferate and differentiate into plasma cells (secrete antibodies) and memory cells

Question 22

what are T-indpendnet antigens?

Answer 22

B cells do not require Th cells for activation

Question 23

primary antibody response

Answer 23

following infection or vaccination

antibodies appear in serum after several days

Question 24

during the lag period, b cells that bind antigens differentiate into:

Answer 24

antibody-producing plasma cells (first IgM->IgG)

Question 25

secondary antibody response

Answer 25

via a second exposure to a pathogen or booster dose

due to memory b cells

a much bigger response with mostly IgG

basis for immunization

Question 26

what are the protective mechanisms of binding antibodies to antigens?

Answer 26

Agglutination- reduced # of infectious units to be dealt with

opsonization-coating antigen with antibody enchancespahgocytosis

neutralization-blocks adhesion of bacteria and viruses to the mucosa

activation of complement-causes inflammation and cell lysis

antibodies attached to target cells destroy by macrophages, eosinophils, and NK cells

Question 27

what is cell-mediated immunity?

Answer 27

it involves T cells

Question 28

what do t cells do in cell-mediated immunity?

Answer 28

recognize antigens that are presented to them on the surface of cells infected with intracellular pathogens

Question 29

what are T cytotoxic cells?

Answer 29

differentiate into cytotoxic lymphocytes

target self-cells altered by infection with pathogen( viruse & bacteria);cancer cells

Question 30

what do T cytotoxic cells do?

Answer 30

recognize endogenous antigens combined with MHC class I molecules via CTL CD8+ co-receptor

Question 31

What do T cytotoxic cells kill?

Answer 31

kill target cells via perforin orations and induction of apoptosis by the introduction of granzymes into the target cell

Question 32

what do T helper cells recognize?

Answer 32

antigens presented by antigen-presenting cells (APCs)

specifically dendritic cells and macrophages

Question 33

How do CD4+ co-receptors help T helper cells?

Answer 33

allows T helpers to bind antigens combined with MHC class II molecules on the APCs

Question 34

what does the activation of T helper cells cause?

Answer 34

release of various cytokines

Question 35

t helper 1 cells:

Answer 35

cytokines activate macrophages, complement, promote inflammation & opsonization, & differentiation of CTLs

Question 36

T helper 2 cells:

Answer 36

cytokines mainly for antibody production by B cells

Question 37

naturally acquired
ACTIVE

Answer 37

active: antigens enter the body naturally body induces antibodies

Question 38

naturally acquired
PASSIVE

Answer 38

passive: antibodies pass from mother to fetus via placenta or to infant

Question 39

Artificially acquired
ACTIVE

Answer 39

antigens are introduced in vaccines;
body produced antibodies

Question 40

Artificially acquired
PASSIVE

Answer 40

preformed antibodies in immune serum are introduced by infection

Question 41

which antibody is the response is fastest, largest, and longer, and what causes it?

Answer 41

secondary antibody response

due to memory B cell