Ch 5 Antibody Structure/Function

Question 1

Immunoglobulin

Answer 1

Glycoprotein in serum, 82% to 96% polypeptide and 2% to 14% carbohydrate, gamma band pH 8.6

Question 2

Tetrapeptide

Answer 2

Heavy H chain (G, M, A, D, E), light L chain (Kappa, lambda, one in all Ig) with disulfide interchain bridge

Question 3

unique variable region (amino-terminal end)

Answer 3

specific binding to a particular antigen

Question 4

Hinge Region

Answer 4

Segment of H chain between the CH1 and CH2 regions, Two antigen-binding sites can operate independently, initiation of complement cascade and Fc receptor binding

Question 5

Carbohydrate (Igs)

Answer 5

in all classes, between CH2 domains of the two H chains, increase solubility of immunoglobulin, protection against degradation, enhances functional activity of the Fc domains

Question 6

Fab fragment

Answer 6

One L chain plus one-half of an H chain held together by S=S, Contains antigen-binding sites

Question 7

Fc fragment

Answer 7

The carboxy-terminal halves of two H chains held together by S=S, effector functions of Igs

Question 8

Pepsin

Answer 8

cleaves Ig above the set of disulfide bonds that hold the heavy chains together, creates F(ab’)2

Question 9

F(ab’)2

Answer 9

two antigen-binding sites held together, Fc’ portion in nonfunctional pieces

Question 10

Isotype (antigenic determinants)

Answer 10

Unique amino acid sequences common to all Igs of a given class or subclass, same in all individuals of a species, differ between species, GMADE

Question 11

Allotype

Answer 11

Minor variations of amino acid sequences that are present in some individuals of the same species but not others, Located in the constant regions of the IgG subclasses, one IgA subclass, and the lambda light chain

Question 12

Idiotype

Answer 12

Variations in variable regions that give individual antibody molecules specificity, Located in amino terminal regions of heavy and light chains

Question 13

immunoglobulin fold

Answer 13

cylindrical structure captures antigen, Antigen binds to hypervariable regions containing CDRs

Question 14

IgG

Question 15

IgM

Question 16

IgA

Question 17

IgD

Question 18

IgE

Question 19

theory of clonal selection for antibody formation

Answer 19

Jerne and Burnet: Lymphocytes are genetically preprogrammed to produce one type of Ig, specific antigen finds the particular cells capable of responding to it, causing them to proliferate, require large number of genes

Question 20

Dryer and Bennett

Answer 20

Constant and variable portions of immunoglobulin chains are coded for by separate genes

Question 21

Susumu Tonegawa

Answer 21

Specific Ig gene segments are selected and joined together during B-cell maturation

Question 22

Clonal Selection

Answer 22

Each B cell has a BCR specific for a particular antigen, antigen enters the body, it binds only to the B cells that possess BCRs specific for it, only those B cells proliferate and differentiate into plasma cells

Question 23

Ig genes

Answer 23

H chain genes on chromosome 14,
κ chain genes on chromosome 2,
λ chain genes on chromosome 22
Rearrangement of genes to produce functional antibody molecules

Question 24

Junctional diversity
(Antibody Diversity)

Answer 24

Joining of V, J, and D segments does not always occur at a fixed position

Question 25

Somatic hypermutation

Answer 25

Genetic mutations during the course of the immune response that result in stronger binding of antigen (affinity maturation)

Question 26

Monoclonal Antibodies (Georges Kohler and Cesar Milstein)

Answer 26

laboratory testing and therapy, hybridoma - hybrid cell line, single antibody-producing B cell and a myeloma cell