Monoclonal Antibody Against a Human Sperm Protein Recognizes Multiple Epitopes on Rabbit and Human Sperm and Blocks Sperm Function

Abstract

A monoclonal antibody was raised against a human sperm protein of apparent molecular size of 40 kDa. Of the 6 hybridoma clones selected for study, one clone (B-12) was chosen for further investigations. The antibody secreted by the clone agglutinated human and rabbit spermatozoa in vitro. The antibody belonged to IgM class. In indirect immunofluorescence studies this antibody reacted to acrosome of living human and rabbit spermatozoa. On fixed sperm of the same species it recognized midpiece and parts of tail along with the acrosome. Mouse, hamster, guinea pig, monkey and rat sperm showed similar localization. Interaction between rabbit sperm and oocyte was inhibited in vitro by this antibody. On western blots of human and rabbit sperm extracts the antibody recognized more than one epitope.

Antibody‐induced changes on rabbit sperm surface inhibit gamete interaction

“…These proteins had cross-reactive epitopes to these antigens present in rat testes which play a role in fertility (Shaha et al, 1990aShaha et al, 1991). This particular monoclonal antibody inhibited rabbit sperm oocyte interaction (Shaha et al, 1993). The observations reported here include patching and capping of proteins on rabbit sperm surface with their eventual shedding.…”

“…My goal was to study the events occurring on rabbit sperm surface molecules in response to antibody binding. The monoclonal antibody used in this study was against human sperm proteins of 40kDa size which cross-reacted with rabbit sperm proteins of similar molecular weight (Shaha et al, 1993). It also inhibited rabbit sperm-oocyte interaction when sperm were preincubated at 37°C for 15 min with the antibody prior to incubation with the oocyte (Shaha et al, 1993).…”

“…The monoclonal antibody used in this study was against human sperm proteins of 40kDa size which cross-reacted with rabbit sperm proteins of similar molecular weight (Shaha et al, 1993). It also inhibited rabbit sperm-oocyte interaction when sperm were preincubated at 37°C for 15 min with the antibody prior to incubation with the oocyte (Shaha et al, 1993). 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.…”

“…For all experiments a murine monoclonal antibody against the 40 kDa antigen was used. The monoclonal antibody was of IgM type (Shaha et al, 1993). For some experiments a polyclonal antibody recovered from mouse immunized for raising monoclonal antibodies was used.…”

“…In this article I report my observations on changes in the mobility of rabbit sperm surface proteins induced by a monoclonal antisperm antibody (Shaha et al, 1993) raised against human sperm proteins of 40kDa size. This antibody cross-reacted with rabbit spermatozoa, and recognized similar antigens such as those of human sperm as revealed by Western blots (Shaha et al, 1993). The rabbit was chosen as a model as it was possible to obtain nonacrosome-reacted sperm in large numbers from rabbit cervixes (Overstreet and Cooper, 1979).…”