Idiotype-specific regulation might contribute to specific unresponsiveness in dextran-primed mice.

Priming of adult responder mice with optimal immunogenic doses of dextran alpha, 1-6 results in reduced antibody responses to secondary antigenic challenge. We have now quantitated dextran-specific clonal precursors in the large and small B-lymphocyte compartments within several days or several months after priming with either dextran or antiidiotypic antibodies directed to a dominant idiotype of C57BL/6 mice which accounts for more than 50% of the antibody response. The results show that "secondary unresponsiveness" correlates with idiotype-directed depletion of the appropriate specificities from the immunocompetent resting B-cell pool.