Carrier-dependent selectin of antibody clones and classes during the immune response.

The selection of antibody clones and antibody classes during the immune response to the hapten oligo-D-alanine was found to be carrier dependent. When the hapten was coupled to a T-independent antigen (streptococci) a restricted immune response of IgM and IgG antibodies was induced. When the hapten was coupled to a T-dependent antigen (ovalbumin) a heterogenous response of only IgG antibodies was found. The carrier had an effect on the affinity of IgG but not of IgM antibodies. Clonal pattern and class distribution were fixed early in the immune response. Second and third immunizations with a heterologous carrier elicited the same clonal pattern and class distribution in the secondary response as that found with the original carrier.