Antibodies to Spermatozoa in Male Monkeys: Mode of Action**Publication No. 990 from the Oregon Regional Primate Research Center. Supported by Northwestern University/PARFR Subcontract 70N under Subcontract AID/csd-3608, National Institutes of Health Grant RR000163 and Contract NO-1-4-2866.††Presented in part at the Thirty-Fourth Annual Meeting of The American Fertility Society, March 29 to April 1, 1978, New Orleans, La

Hemizona assay (HZA) demonstrates effects of characterized mouse antihuman sperm antibodies on sperm zona binding

Characterized antihuman sperm monoclonal antibodies from mice were evaluated using the hemizona assay (HZA) to determine whether sperm:zona binding was effected. The seven monoclonal antibodies were characterized using human sperm in agglutination, immobilization, and penetration assays. Semen was provided by four fertile men and used in the HZA to determine if the presence of a monoclonal antibody would affect tight binding of the sperm to the zona pellucida. Pre-incubation of MA-14 for 1 h with the sperm induced a 33-54% reduction of the number of tightly bound sperm. This antibody reacts to an antigen located on the acrosome and midpiece. Experiments in which there was no pre-incubation of the antibody with sperm, resulted in no significant reduction in the number of sperm bound in the HZA. These findings suggest that an anti-human sperm antibody produced in mice can modulate sperm:zona binding. Reduction in zona binding could indicate a cause of immune-related infertility and this test may be useful in selecting an antigen for contraceptive vaccine development.

Epididymal fluid macromolecules do not act as auto- or alloantigens

Because epididymal secretory glycoproteins form important functional associations with maturing spermatozoa, the possibility has been explored that epididymal antigens might be useful in contraceptive vaccine development. Male and female rabbits, hamsters, and rats were immunized for several weeks with epididymal fluid, initially either with complete Freund's adjuvant, or conjugated with glutaraldehyde. Some female rabbits were also immunized using albumin-free rabbit epididymal fluid. The sera of all the immunized animals were then examined for autogenous, allogeneic, or [in guinea pigs also] xenogeneic immune responses, using immunodiffusion and ELISA techniques. In each instance, xenogeneic immunization produced a marked antibody response. However, no animals developed any detectable antibody reactive with epididymal fluids following auto- or alloimmunization (ie with fluid from the same species), and they remained fertile even when immunized males were mated with immunized females. Furthermore, when female rabbits were immunized with ejaculated rabbit spermatozoa, they produced antibodies reactive only with the sperm homogenate, but not with any epididymal fluid component. These results indicate that macromolecules secreted by the epididymis, including those that associate with spermatozoa, do not act as auto- or alloantigens and, at present, would seem to have no immediate promise for contraceptive vaccine development in males or females.

Immunoglobulin classes, secretory component, and sperm agglutinins in semen after vasovasostomy

The immunoglobulin classes of the sperm-agglutinating antibodies in the seminal fluid and serum from four vasovasostomized men, as well as in operatively obtained testis-epididymis fluid from two of them, were investigated by specific solid-phase absorption of IgG, IgM, and IgA. In two patients the major part of the seminal agglutinins was IgA, and in one IgG, indicating that both local production and diffusion of sperm agglutinins from serum to the testis-epididymis compartment may take place. The total levels of immunoglobulins in seminal fluid generally increased after the operation, and IgM was present in two postvasovasostomy samples. This suggests a pathotopic potentiation effect of the vasectomy on the epithelial lining of the testis-epididymis compartment. Comparison of the results of solid-phase absorption with anti-IgA and anti-secretory component (SC) pointed to the presence of "free" SC in postvasovasostomy seminal fluid.

Primates: Their use in research on vasectomy

Studies based on experimental vasectomies clearly reveal marked species differences in response to vasectomy. In rats, vasectomy invariably results in granuloma formation at the surgical site. In rabbits, immune-complex orchitis develops. Allergic orchitis may also develop in guinea pigs, and the morphological lesions can be adoptively transferred. My co-workers and I have been able to study systematically, biochemically, hormonally, pathologically, and immunologically, primates vasectomized up to 14 years earlier and to compare them with age-matched controls. We have monitored antibody levels in vasectomized rhesus and cynomolgus macaques by sperm-agglutination, sperm-immobilization, and indirect immunofluorescence techniques. Antibodies develop in almost every monkey, in some as early as 10 days after vasectomy. About 50% retain such circulating antisperm antibodies. In men, antibody development is less rapid, and about half of vasectomized men reveal detectable levels. Testicular histopathological studies have revealed detectable levels. Testicular histopathological studies have revealed orchitis, aspermatogenesis, or both, resembling allergic orchitis in most of the vasectomized monkeys and in about one-fourth of the controls. Limited studies of human material reveal some testicular changes. Epididymitis and epididymal granuloma occur exclusively in the vasectomized animals. Use of immunofluorescence has revealed significantly more granular deposits of IgA, IgG, and/or C3 in the basal lamina of the ductus efferens and the caput epididymidis of the vasectomized monkeys. Similar studies on human material have not been done. Both cynomolgus and rhesus macaques have proved to be excellent models for research in atherosclerosis and so have been used to determine whether constant sperm antigen leakage causes immune-complex formation that might result in arteritis and atherosclerosis. Evaluation of the cardiovascular systems from such animals has revealed that vasectomized monkeys have more frequent, more extensive, and more severe arteriosclerosis than age-matched controls. Epidemiological studies are currently under way to determine whether such an effect also occurs in men after vasectomy.