Origin of the Antigens in Rabbit Semen Which Induce Antifertility Antibodies

Abstract

Summary. Cattle and guinea-pig antisera against rabbit testis, epididymal spermatozoa and ejaculated semen had high titres of sperm agglutinins and prevented fertilization of ova in rabbits bred with semen treated with these sera. Although cattle antisera produced against seminal plasma from vasectomized rabbits, 9-day-old-rabbit conceptuses and rabbit brain and guinea-pig antiserum to seminal plasma containing epididymal secretions exhibited relatively high titres of sperm agglutinins, none of these sera prevented spermatozoa from fertilizing ova. The antifertility antibodies were removed or inactivated in antisera by absorptions with testis material, epididymal spermatozoa and semen supernatant but not by absorption with either type of seminal plasma.Agar-gel diffusion and immuno-electrophoretic techniques revealed that ejaculated rabbit semen contained at least nine antigens. Seven were common to seminal plasma, two to blood serum and two appeared to be spermatozoa-specific originating in the testis. Antisera to the conceptus material reacted with four to six different antigens in semen of which at least one was not common to the antigens in blood serum.

Differentiation of Rabbit Sperm Antigens From Those of Seminal Plasma

“…This sterility was produced by antibodies against sperm-specific antigens rather than the sperm-coating antigens (Menge & Protzman, 1967). In the female rabbit, Weil & Roberts (1965) demonstrated that the formation of antibodies against rabbit seminal plasma had no effect on fertility.…”

Induced Infertility in Cattle by Iso-Immunization With Semen and Testis

“…Embryo mor¬ tality was also induced in 9-day-old rabbit embryos by direct contact with this bovine antiserum (Menge, Kiddy, Stone & Casida, 1962). Menge & Protzman (1967) (Behrman & Nakayama, 1965) and mice (McLaren, 1964 (Pierce, 1953;Kerr & Robertson, 1953;Kerr, 1955;Terpstra, 1956). The conflicts may arise partially because of a gradient phenomenon, in that unless the circulatory titre of antibody is high the amount of antibody in the secretions of the genital tract may be diluted to such an extent that it is difficult to detect.…”

Reduction of Fertility in Female Mice Iso-Immunized With a Sub-Cellular Sperm Fraction

“…Plank (1967) noted that few spermatozoa ever reached the oviduct in iso-immunized guinea-pigs, and those that did were immotile shortly after mating. Rabbit spermatozoa which had been incubated in vitro with heterologous anti-sperm sera were alive at the time of insemination, but failed to fertilize rabbit eggs (Menge & Protzman, 1967). It seems probable that this was due to a cytotoxic action on the antibody-sensitized sperm cells in the re¬ productive tract following contact with complement in vivo.…”