antigen-antibody interactions

Antigen-Antibody Interactions

Serology - in vitro demonstration of Ag/Ab reaction

Ag/Ab reaction = reversible1. Primary interactions

1) Electrostatic interactions2) Hydrogen bond3) Hydrophobic interactions4) van de Waals force

2. Secondary interactionsPrecipitationAgglutinationComplement activation reactions

Association constant

Ab + H AbH (binding of hapten)

K = [AbH]/[Ab][H] (association constant between reactants)

Affinity = binding of Ab with epitope characterized by association constant

Avidity = binding energy between Ab & multivalent Ag IgM > IgG

Figure 5.1Reactions between antibody or antibody fragments and antigens or hapten.

Figure 5.2

A representation of the anti-immunoglobulin (Coombs) test.

Agglutination inhibition (Early home pregnancy test kit)

Figure 5.3

A representation of the precipitin reaction.

Figure 5.4Gel diffusion by antibodies and a single antigen (A) and antibodies to

antigens 1, 2, 3, and their respective antigens (B).

Figure 5.5Double gel-diffusion patterns showing pattern of identity (left), pattern of nonidentity (center), and pattern of partial identity (right).

Figure 5.6Radial diffusion, A, B, C, D, and E represent known concentrations of antigen; F and G represent unknown concentrations that can be

determined from the graph.

Figure 5.7

Patterns of immunoelectrophoresis of serum proteins.

Figure 5.8Western blots of serum samples from two HIV-infected individuals and one control subject.

Figure 5.9Amount of label bound to antibody after incubation of constant amounts of antibody and labeled antigen.

Figure 5.10Radioimmunoassay, based on the competition of nonlabeled and labeled antigens for antibody.

Solid phase radioimmunoassay (RIA) todetect hepatitis B virus in blood serum

Figure 5.11A representative ELISA using a well coated directly with antigen

Immunoprecipitation

Immunofluorescence

Figure 5.12A schematic representation of a fluorescence-

activated cell sorter (FACS).

Flow cytometry & leukemia typing

Figure 5.13

A schematic representation of the production of monoclonal antibodies.

Figure 5.14A general procedure for producing transgenic mice.