Genetic control of the immune response to staphylococcal nuclease. IV. H-2-linked control of the relative proportions of antibodies produced to different determinants of native nuclease.

The relative proportions of antibodies of different specificities within antisera raised to native staphylococcal nuclease have been studied in several strains of mice in which the antibody response has been shown to be under H-2-linked Ir-gene control. A method was developed in which binding to different radiolabeled fragments of nuclease was titrated against increasing fragment concentration until the binding capacity of the antiserum for that fragment was saturated. In comparing the low responder (H-2b) strain C57BL/10 with its congenic high responder counterpart B10.A (H-2a), it was found that the two strains made markedly and reproducibly different proportions of antibodies to different determinants on native nuclease. Since these two strains differ only at H-2, and therefore have identical immunoglobulin structural gene repertoires, we conclude that H-2-linked Ir genes can control the response to different determinants on the same antigen molecule independently of one another. This result suggests a possible role of H-2-linked genes in the selection of specific B cells.