Objective: To examine the receptor-ligand interaction between E. coli and spermatozoa resulting in sperm immobilization.
Methods: Sperm immobilization factor (SIF) was isolated and purified from filtrate of E. coli suspension. Receptor on human spermatozoa for SIF was made to isolated and purified by salt extraction, gel permeation and ion exchange chromatography. Receptor dependent immobilization of spermatozoa by SIF was confirmed by competitive inhibition by addition of the purified receptor and binding to sperm receptor by Fluorescin Isothiocynate (FITC) labelled SIF using fluorescence microscopy.
Results: Heat labile, non-dialyzable, sperm immobilization factor of ∼56 kDa was isolated and purified from E. coli. Using SIF as a tool, receptor of 113 kDa could be isolated and purified from human spermatozoa. Addition of purified receptor completely inhibited sperm immobilization and death induced by SIF suggesting receptor-dependent immobilization of spermatozoa. Further incubation of sperm with FITC labelled SIF resulted in staining of whole sperm.
Conclusion: The study provides evidence of receptor-ligand interaction between E. coli and spermatozoa.
© 2011 The Japanese Urological Association.