Influence of Antisperm Antibodies on Human Sperm Function

Abstract

Antisperm antibodies have been found in about 8% of men with infertility and in 60 to 80% of patients following vasectomy. In order to investigate the way antibodies influence sperm function we studied serum and seminal plasma from patients with infertility (n = 61) or undergoing vasovasostomy (n = 25). These antisera were characterised to determine their TAT titre, the nature of the target antigens and their capacity to interfere directly with fertilisation. The results indicate that antibodies from both groups of patients exhibit a capacity to stimulate or suppress sperm/oocyte fusion. The proportion of samples showing stimulatory activity was higher (50%) in the vasovasostomised population than in patients with infertility (21%). The remainder of the antisera suppressed sperm/oocyte fusion. There was no correlation between the titre of antisperm antibodies and their capacity to influence sperm function, indicating that it is the nature of the target antigens which is of significance rather than the antibody concentration. Western blot analysis indicated that these antisera targeted a group of sperm surface antigens with molecular weights of 30kD (35,45,66,90 and 115kD). Monoclonal antibodies are now being prepared in order to determine which of these specific components are involved in the suppression of sperm function.

Vasovasostomy Results in 66 Patients Related to Obstructive Intervals and Serum Agglutinin Titres

“…Meinertz et al [9] also stressed the finding that especially the occur rence of IgA in the seminal fluid was associated with low conception rates. Aitken et al [10] described the capacity of antibodies to stimulate or suppress sperm/oocyte fu sion. In vasovasostomized patients they saw a higher stimulating effect on this fusion than in patients with pri mary infertility.…”

Naturally-occurring antisperm antibodies in men: interference with fertility and implications for treatment

“…In fact either inhibition (133)(134)(135), or enhancement (136), both inhibition and enhancement (106,137), or no effect were found (138,139). Some discrepancies may be explained by procedural differences.…”

“…Some discrepancies may be explained by procedural differences. Generally, when inhibitory effects were reported, donor sperm were exposed to ASA after capacitation or directly into the insemination medium: in any case, free antibodies were not removed before sperm/oocytes coincubation (106,134,135). Using this procedure, an interaction of ASA with internal sperm antigens, which can be revealed after the acrosomal loss, has been supposed to explain the inhibitory effect (140).…”

Naturally-occurring antisperm antibodies in men interference with fertility and implications for treatment

“…Finally, the demonstration of the actual responsibility of ASA in impairing cervical mucus penetration has been provided by matching donor sperm suspensions exposed to sera containing ASA against the same sperm suspensions exposed to control sera without ASA (106).…”

“…With this assumption, the study of clinical infertility due to ASA, regarded as "experiments of nature" in fertility reduction, has been approached to identify candidate sperm antigens for immunocontraceptive development (193,194). Numerous investigators have reported the identification of specific antigens using sera from WHO reference bank or from independent collections (106,(195)(196)(197)(198)(199)(200)(201)(202)(203)(204)(205)(206). However, characterization of sperm antigens was limited to SDS-Page in most studies, and results varied widely due to the methods and reagents employed.…”