Receptor from Streptococcus pyogenes as a potential antidote against sperm immobilization factor-induced sperm impairment and infertility.

The present study was undertaken to demonstrate the existence of mimicry between spermatozoa and bacteria. For this, the shared antigenic determinants between mouse spermatozoa and Streptococcus pyogenes against a common ligand, sperm immobilization factor (SIF), were isolated. The mimicry was established on the basis of their ability to ameliorate the SIF-mediated compromised sperm parameters in vitro viz. motility, viability, morphology and Mg2+-ATPase activity of spermatozoa. Further, both the receptors i.e. SIF-binding receptor from mouse spermatozoa (MS-SBR) and SIF-binding receptor from S. pyogenes (S-SBR) were able to block the binding of FITC-labelled SIF to spermatozoa and bacteria. The in vivo studies also showed that MS-SBR (10 μg)/S-SBR (25 μg) could alleviate SIF-induced infertility in female BALB/c mice, further providing evidence for molecular similarities between bacteria and spermatozoa.