Qualitative differences in sperm antibody responses in mice of different inbred strains and sexes

To better understand the immunogenetic basis and potential pathological consequences of anti-sperm humoral immunity, age-matched female mice of 9 different inbred strains were immunized with syngeneic sperm and were tested for qualitative (specificity) and quantitative (titer) antibody differences by radioimmunoassay, immunofluorescence and immunoblot techniques. All mice developed antisperm antibodies, although titers varied considerably between inbred strains. Antisperm antibodies produced in this study did not cross-react with membrane antigens on thymocytes, brain or immature testicular germ cells. Immunoblot tests identified 17 major sperm antigen bands; this approach also revealed considerable inter- and intra-strain variation in antisperm antibody specificities among female mice. In a parallel study C57BL/6 male mice demonstrated significantly lower antisperm antibody titers and an absence of response to certain sperm antigens in immunoblot tests when compared to age-matched females of the same inbred strain. These findings provide evidence that genetic factors (including sex) interact with environmental (nongenetic) factors in the control of immune responses to sperm antigens.