DNA immunization against proacrosin impairs fertility in male mice.

Problem Evaluation of proacrosin/acrosin ability to induce an immune response in male mice after genetic immunization and assessment of animal fertility. Method of study Mice received 50 mu g per animal of a plasmid containing the human proacrosin cDNA (pSF2-Acro) (control: empty plasmid, pSF2). The humoral response was evaluated by ELISA and immunocytochemistry. In vivo fertility was assessed by mating immunized males with control females. The effect of antibodies upon Ca+2-ionophore-induced acrosomal exocytosis (AE) and in vitro spermzona pellucida (ZP) binding was also studied. Results pSF2-Acro-immunized mice developed high levels of specific antibodies (P < 0.05) that recognized the sperm acrosomal cap. The number of fertile mice was lower (P = 0.027) in pSF2-Acro-immunized animals than in controls. Litter size was smaller (P < 0.05) in the pSF2-Acro group compared with controls. A negative correlation (P < 0.05) between antibody levels and litter size was found. Antiproacrosin/acrosin antibodies inhibited spermZP binding (P < 0.0001) and Ca+2-ionophore-induced AE (P < 0.05). Conclusion DNA immunization against proacrosin elicits an immune response in male mice associated with abnormal sperm functions and reduced fertility.