Disruption of ectoplasmic specializations between Sertoli cells and maturing spermatids by anti-nectin-2 and anti-nectin-3 antibodies.

AIM To understand the biological functions of the ectoplasmic specializations between Sertoli cells and maturing spermatids in seminiferous epithelia. METHODS In order to disrupt the function of the ectoplasmic specializations, nectin-2, which is expressed at the specialization, was neutralized with anti-nectin-2 antibody micro-injected into the lumen of the mouse seminiferous tubule. Anti-nectin-3 antibody was also micro-injected into the lumen in order to neutralize nectin-3, which is expressed at the specialization. RESULTS The actin filaments at the specialization disappeared, and exfoliation of maturing spermatids was observed by electron microscopy. CONCLUSION Nectin-2 was neutralized by anti-nectin-2 antibody and nectin-3 was neutralized by anti-nectin-3 antibody, respectively. Inactivated nectin-2 and nectin-3 disrupted the nectin-afadin-actin system, and finally the actin filaments disappeared. As a result, the specialization lost the holding function and detachment of spermatids was observed. One of the functions of the specialization seems to be to hold maturing spermatids until spermiation.