Localization of adhesion molecules on human spermatozoa by fluorescence microscopy.

The expression of adhesion molecules on human spermatozoa of healthy probands was analysed. The localization patterns of adhesion molecules (AM) on the spermatozoal surface were documented by fluorescence microscopy. Spermatozoa were incubated with antibodies against alpha 1 (CD49a), alpha 2 (CD49b), alpha 3 (CD49c), alpha 4 (CD49d), alpha 5 (CD49e), alpha 6 (CD49f) chains of beta 1 integrins, beta 1 (CD29), beta 2 (CD18), alpha V (CD51), beta 3 (CD61) and beta 4 integrin chains, the LFA-3 (Lymphocyte function antigen, CD58) from the immunoglobulin superfamily and the extra-cellular matrix proteins laminin, fibronectin and collagen IV. For collagen IV, alpha 1 and alpha 2 chains no expression could be noticed. Laminin was detected at the acrosomal membrane, fibronectin and beta 4 chain mainly at the equatorial membrane. The fibronectin receptors alpha 3, alpha 4 and alpha 5 chains of the beta 1 integrins were mainly located on acrosomal and equatorial membrane areas. Laminin receptor alpha 6 chain was located postacrosomal and less frequently acrosomal. beta 2 chain and vitronectin receptors alpha V and beta 3 chains had a mainly postacrosomal localization pattern. LFA-3 was found constantly on postacrosomal membrane areas. Double staining technique was used to prove the simultaneous occurrence of fibronectin and its integrin receptors alpha 3, alpha 4 and alpha 5 chains and of alpha V and beta 2 chains on spermatozoa. The localization patterns of integrins on double stained spermatozoa were similar to the patterns described for single stained spermatozoa. The localization of fibronectin appeared to be influenced by the presence of integrins: the typical equatorial fibronectin band disappeared in case of an equatorial localization of integrins.