Ch 24

Question 1

types of adaptive immune responses

Answer 1

humoral and cell-mediated

Question 2

antigens are

Answer 2

molecules that in the body activate lymphocytes

Question 3

cells that interact with antigens

Answer 3

B cells - via surface immunoglobulins
T cells - via surface antigen receptors

Question 4

epitopes that elicit an immune response can be a

Answer 4

protein, peptide, or complex polysaccharides

Question 5

interaction with antigens occurs with smaller segments called

Answer 5

epitopes or antigenic determinants

Question 6

_____ of these chains possess variable amino acid sequences and are the ______

Answer 6

variable regions;
antigen-binding sites

Question 7

the Fc region binds to

Answer 7

host cell receptors

Question 8

antibody classes

Answer 8

IgG, IgD, IgE are monomer forms
IgM and IgA are aggregates of 2 or more monomers

Question 9

antibody isotypes

Answer 9

differ in amino acid sequence of constant region of heavy chains

Question 10

antibody idiotype

Answer 10

possess same amino acid sequence of constant region of heavy chains, but differ in regions of antigen binding sites

Question 11

IgA

Answer 11

dimer; found mainly on mucosal surfaces & in secretions. prevents pathogen attachement to surfaces
(15%)

Question 12

IgG

Answer 12

monomer; most abundant in blood & tissue fluids; opsonization, activate complement; neutralize viruses
(75%)

Question 13

IgD

Answer 13

found on B cells & in blood, lymph
(0.2%)

Question 14

IgM

Answer 14

circulating type is a pentameter; generally remains in blood vessels. First Ab detected in immune response; effective in agglutination & complement activation
(10%)

Question 15

IgE

Answer 15

found on surface of mast cells & basophils; causes release of histamine, other chemicals by these cells in presence of antigen. can attract complement, phagocytic cells
(0.2%)

Question 16

protective mechanisms of binding antibodies to antigens

Answer 16

agglutination
opsonization
neutralization
activation of complement
antibody dependent cell-mediated cytotoxicity

Question 17

the humoral immune response to a microbe is a composite of responses to different epitopes by

Answer 17

thousands of B cells; most effective against extracellular pathogens

Question 18

B cells possess ____ that bind to _____

Answer 18

surface immunoglobulins;
their specific epitope -> B cells become activated

Question 19

B cells usually require T helper cells that

Answer 19

interact with each other
called T dependent antigens
Th cells bind antigen via MHC class 2 receptors on B cells

Question 20

The key to the B cell response is

Answer 20

clonal selection: proliferation of B cells that respond to a specific antigen

Question 21

when a B cell contacts its cognate antigen

Answer 21

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

Question 22

T independent antigen

Answer 22

B cells do no require Th cells for activation

Question 23

primary antibody response

Answer 23

following infection or vaccination; antibodies appear in serum after several days
during lag period, B cells that bind antien differentiate into antibody producing plamsa cells and meemory B cells

Question 24

secondary antibody response

Answer 24

via second exposue to pathogen or booster dose
due to memory B cells
a much bigger response with mostly IgG
basis for immunization

Question 25

Cell mediated immunity involves

Answer 25

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

Question 26

T cytotoxic cells

Answer 26

differentiate into cytotoxic T lymphocytes; target self-cells altered by infection with pathogen - als target cancer cells

Question 27

naturally acquired active adaptive immunity

Answer 27

antigens enter the body naturally; body induces antibodies

Question 28

naturally acquired passive adaptive immunity

Answer 28

antibodies pass from mother to fetus via placents or to infant

Question 29

artifially acquired active adaptive immunity

Answer 29

antigens are introuced in vaccines; body produces antibodies

Question 30

artificially acquired passive adaptive immunity

Answer 30

preformed antibodies in immune serum are introduced by injection

Question 31

humoral summary

Answer 31

1. a B cell binds to the antigen for which it is specific. A T-dependent B cell requires cooperation with a T-helper cell
2. The B cell, often with stimulation by cytokines from a T-h cell, differentiates into a plasma cell. some become memory cells
3. Plasma cells proliferate and produce antibodies against the antigen