RIIIS/J mice lack a gene influencing the capacity to make an antibody response to helper T cell-independent antigens.

RIIIS/J mice lack an autosomal dominant gene(s) that has a decisive influence in determining the capacity to make an IgM antibody response to several representative helper T cell-independent antigens; these mice appear to possess functionally active helper T cells because of their ability to make a reasonably good antibody response to SRBC, a helper T cell-dependent antigen. The genetic defect involved cannot be attributed to the absence of B cells capable of giving a mitogenic response to bacterial LPS.