Monoclonal antibody recognizing an apparent peptide epitope of human seminal plasma glycoprotein and exhibiting sperm immobilizing activity

Purification of two murine monoclonal antibodies of the IgM class by hydroxylapatite chromatography and gel filtration

A two-step method using hydroxylapatite chromatography and gel filtration is described for the purification of two murine monoclonal antibodies of the IgM class. Ascites fluid from each hybridoma was diluted in sodium phosphate buffer (0.01 M, pH 6.8), loaded onto a hydroxylapatite column and eluted with a stepwise sodium phosphate gradient. The immunoreactive protein peaks were concentrated and subjected to gel filtration using either Sephadex G-200 or Sephacryl S-200HR. The biological activity of the end-products was confirmed by complement lysis assay and by indirect immunofluorescence and flow cytometry. The purity of the end-products as assessed by SDS polyacrylamide gel electrophoresis and densitometry was at least 90%. The methods described produced immunoreactive material with a high level of purity. The procedure for each antibody was reproducible and provides a reliable method for purification of monoclonal antibodies of the IgM class.

Human sperm proteins from testicular and epididymal origin that participate in fertilization: modulation of sperm binding to zona-free hamster oocytes, using monoclonal antibodies

In order to identify human sperm surface proteins involved in the gamete recognition process, mouse monoclonal antibodies were directed against human spermatozoa and screened with live spermatozoa by enzyme-linked immunosorbent assay (ELISA). Immunoperoxidase staining of human testis showed the early presence of four corresponding proteins on germinal cells, while six were detected primarily in testis fluid. The presence of 17 proteins was evidenced in the epididymis. Eight were detected with a decreasing gradient from the beginning to the end of the organ, including vasa efferentia for three of them. The other nine were observed in only one defined segment, usually the caput epididymis, which was found to be the most active region. Comparison of spermatozoa patterns from testis, vasa efferentia, and the three regions of epididymis pointed out a progressive coating. By contrast, three antibodies displayed a migration of spermatozoa surface domains in the course of epididymal transit. Six antibodies were found to inhibit human spermatozoa adherence to zona-free hamster oocytes, while nine promoted it. Molecular weights of antigens corresponding to nine of the antibodies ranged from 11 to 215 kDa. No correlation could be established with previously described human proteins. These observations emphasize the role of epididymis in human sperm maturation.