Regional binding of human anti-sperm antibodies assessed by indirect immunofluorescense

Abstract

Indirect immunofluorescence (IIF) can be a powerful tool for determining the site on spermatozoa to which antibodies bind. Human sera that contain anti-sperm antibodies are often of low titre, and may contain antibodies directed against both intracellular and surface antigens. We have developed an IIF protocol that helps to distinguish intracellular from surface labelling. The two types of labelling were differentiated by exposing the spermatozoa to Hoechst 33258, a nuclear stain of low membrane permeability, to tag the spermatozoa that had disrupted membranes. Surface labelling detected in this fashion was patchy. It was much more uniform if the spermatozoa were fixed in paraformaldehyde, or if a univalent, Fab fragment was used as the second antibody. Thus, it is likely that most of the patchy appearance is due to the bivalent second antibody cross-linking mobile antigen-antibody complexes. For some sera, patching was so pronounced that it appeared to remove the label from portions of the sperm surface, giving a misleading picture of the regions to which the antibodies were directed. Fourteen sera were used in IIF and none of them labelled spermatozoa solely on the head or on the tail.

Testicular Isoform of Angiotensin I‐Converting Enzyme (ACE, CD143) on the Surface of Human Spermatozoa: Revelation and Quantification Using Monoclonal Antibodies

“…The antibody‐induced shedding of ACE also was described 42 . Cross‐linking of sperm surface antigens by multivalent antibodies or antigen–antibody complexes by second antibodies can also be accompanied by aggregation and shedding of these complexes 46–49 . Previously, we showed the shedding of antigen–antibody (Ag–Ab) complexes from the sperm surface at low temperature 50 .…”

Antibody‐induced changes on rabbit sperm surface inhibit gamete interaction

“…Therefore, rabbit sperm from cauda epididymis and cervix were used in this study. Antibody-induced patching on spermatozoa was previously reported (Gaunt et al, 1983;ORand, 1977), as was antibody-induced translocation of antigen on human and sea urchin sperm (Trimmer and Vacquire, 1988;Cross and Moore, 1990). The idea behind the present study was to investigate the behavior of antigen antibody complexes on viable sperm from relevant regions of the reproductive tract under conditions of different temperatures and treatments, and to study their relationship to sperm oocyte binding.…”

“…Although it is known that sperm-bound antibodies can impair fertilization (Francavilla et al, 1992), and that this can be correlated to infertility (Peters and Coulam, 1992), the fate of the surface proteins on antibody binding and subsequent effects on sperm function is not fully understood. Sera from patients with antisperm antibodies were shown to induce patching of antigens on the human sperm surface (Cross and Moore, 1990). However, subsequent events were not reported.…”