A hierarchy of responsiveness and the production of nonprecipitating antibodies to F antigen

The immune response to F antigen by a variety of inbred strains and F₁ hybrids has been studied. All of the mice responding to appropriate preparations of F antigen share ak allele atH-2K orI-A. In F₁ hybrids, however, this permissive gene is sometimes expressed as dominant responsiveness, while in other combinations as dominant nonresponsiveness. There appears to be a hierarchy of responsiveness among the responder strains tested. Finally, some strains produce nonprecipitating antibodies against F antigen which may represent a genetically controlled restriction of the response to this antigen.