Vasectomy-induced autoimmunity: monoclonal antibodies affect sperm function and in vitro fertilization

A panel of sperm-reacted monoclonal auto-antibodies developed from spleen cells of vasectomized mice (BDF1) were characterized. Immunogenic antigens were mainly located on the acrosome, midpiece and principal piece. All of the monoclonals were IgM; three demonstrated a multispecific reaction with testis and/or epididymis antigen extracts by immunoblotting. Immunobead studies indicated that most of the antibodies were to surface molecules, a finding supported by the observation that five of the seven antibodies caused complement-mediated immobilization (although not sperm agglutination) of mouse sperm. In vitro fertilization was significantly impaired when antibodies (Vx5, 8 and 10) were added to the sperm prior to exposure to the eggs. Furthermore, passive immunization with Vx5 antibody reduced in vivo fertilization. Our findings indicate that vasectomy-generated antibodies can reduce sperm function in vitro and in vivo.