The specificity of immunosuppression by alloantibody in the mouse.

The ability of alloantibody to suppress the humoral immune response to transplantation antigens in the mouse has been studied in relation to its specificity. It was found that antibody was able to suppress the cytotoxic antibody response to determinants other than those against which it was directed when there was some common antigenicity between the different H-2 types used for immunising. It was also found that suppression of the response to both parental haplotypes of an F1-hybrid cell could be achieved by antibody to only one parental haplotype, the antibody being made in the other parental strain to avoid any possibility of cross-reactivity. Such nonspecific immunosuppression was not achieved when cells of the two parental strains were administered mixed together.