Unit 3 - Antibodies

Antibodies react with specific regions on the antigen called ___ or ___

antigenic determinants; epitopes

What are the at least two identical sites on each antibody that binds to antigenic determinants?

antigen binding sites

What on the antigen does the antigen binding site bind to?

epitope

A bivalent antibody is a ___

monomer

What are the classes of antibodies called?

immunoglobulins

What are the 5 major classes of immunoglobulins?

IgG, IgA, IgM, IgD, IgE

On antibodies, chains are joined by…

disulfide links

The sections at the end of the Y’s arms are…

variable regions

Upper part of the light and heavy chains is the..

Fab

What is Fab?

fragment antigen-binding region

Lower part of the light chains and the heavy chains is the …

Fc

What is the Fc?

fragment crystallizable region

T/F Fab is on the variable region

true

T/F Fc is on the variable region

false

T/F The Fc region of all antibodies are the same for each specimen

true

75% of all antibodies in serum are of the __ type

IgG

__ antibodies cross the walls of blood vessels and the placenta

IgG

IgG has a __ structure

monomer

IgM has a __ structure

pentamer

5-10% of all antibodies in serum are of the __ type

IgM

Valence of IgG antibodies

2

Valence of IgM antibodies

10

The strength of the binding of antigen/antibody complex is referred to as

affinity

T/F antigen-antibody binding is reversible

true

T/F low affinity antibodies will bind larger amounts of antigen in a shorter time than high affinity antibodies

false

T/F the higher the affinity the antibody, the more dilute the concentration an antibody can be used at

true

Factors that affect antibody-antigen reactions (in vitro_

• temperature

• pH

• ionic composition of buffers and diluents

Each antibody has a minimum of __ antigen binding sites

2

What determines antibody specificity?

variable regions of both the light and heavy chains

Where are antigen-binding sites found?

on the variable region of the antibody

T/F individual antigenic determinants can trigger an immune response

true

What are light and heavy chains?

molecular weight of the polypeptide chains

What does the valance of antibody refer to?

number of antibody binding sites

Affinity equation:

Ab + Ag ⟺ Ab - Ag

T/F exposure to antibodies produce antigens

false

T/F B lymphocytes differentiate in the bone marrow to become T lymphocytes

false

What is the function of copper in the modified myeloperoxidase (MPO) method?

enhancer