IMMUNOGLOBULIN VARIANTS SUMMARY Flashcards
Definition
Class of antibody (e.g., IgG, IgM, (gA)
Isotype
Definition
Minor genetic variations in the constant region of heavy and light chains within a species
Allotype
Definition
Unique variations in the variable region of heavy and light chains, specific to each antibody molecule
Idiotype
LOCATION
Isotype
Heavy chain CONSTANT region (CH)
LOCATION
Allotype
Primarily heavy chain constant region
(CH) and light chain constant region
(CL);
Sometimes variable regions (VH/VL)
LOCATION
Idiotype
Hypervariable regions of both heavy and light chains (VH/VL)
DISTRIBUTION
Present in all healthy individuals of a species
Isotype
DISTRIBUTION
Present in some, but not all, individuals of a species
Allotype
DISTRIBUTION
Unique to each individual antibody molecule
Idiotype
EXAMPLES
Isotype
[gM, IgG, IgA, IgD, IgE
EXAMPLES
Allotype
Gm markers on the IgG heavy chain
EXAMPLES
Idiotype
Each antibody molecule has a unique idiotype determined by the specific amino acid sequence of its antigen-binding site
FUNCTIONAL SIGNIFICANCE
Determines the effector function of the antibody
•e.g., complement activation,
placental transfer
Isotype
FUNCTIONAL SIGNIFICANCE
Contributes to antibody diversity within a species but does not significantly alter antibody function.
Allotype
FUNCTIONAL SIGNIFICANCE
Determines the antigen specificity of the antibody molecule; Each idiotype binds to a unique epitope on an antigen.
Idiotype
