Localisation and capacitation-dependent loss of buffalo sperm-coating antigens shared with rat sperm

Abstract

SummaryThe heterodimeric sperm-coating protein CFS was previously localised on the middle-piece region of rat spermatozoa by anti-CFS rabbit antibodies. CFS-immunorelated antigens were detected in the secretion of the water buffalo seminal vesicle by protein electrophoresis and Western blotting. Spermatozoa from buffalo epididymal cauda were incubated with the rat antigen and, upon immunostaining with anti-CFS antibodies and goat anti-rabbit fluorescein isothiocyanate (FITC)-conjugated IgGs, CFS was found attached on both the post-acrosomal region and the tail. Indirect immunofluorescence analysis permitted the localisation of CFS-related antigens on the same domains of buffalo ejaculated spermatozoa. These results suggest that the buffalo antigens not only share some epitopes with the homologous rat antigen but may also have some of its functional properties. Ejaculated spermatozoa were capacitated in vitro and then assayed for their content of CFS-like antigens. An inverse relationship was found between the levels of capacitation and the amounts of antigens detected, thus suggesting that the in vitro treatment was effective at removing CFS-related proteins from the cell surface. Titration of these proteins to proteins to monitor plasma membrane changes during sperm manipulation or to evaluate sperm quality is proposed.

Inhibition of Capacitation-Associated Tyrosine Phosphorylation Signaling in Rat Sperm by Epididymal Protein Crisp-11

“…Capacitation was independently and virtually simultaneously described by two laboratory groups [27,28] as the time required for sperm to penetrate an egg after having been deposited in the female reproductive tract. Residence in the female tract is required for capacitation in vivo, resulting in the acquisition of hyperactivated motility in many but not all species [1], the loss of or changes in some constituents of the plasma membrane, including proteins and glycoproteins [29][30][31][32], and the acquisition of the ability to undergo the acrosome reaction [1].…”