The expression of αV, α5, β1, and β3 integrin chains on ejaculated human spermatozoa varies with their functional state

Open Access
Publisher Website
Google Scholar
Abstract
Evidence has been presented suggesting the involvement of integrins and their ligands in mammalian fertilization. In this study we asked whether the α5αvβ1 and β3 integrin chains, which form receptors for fibronectin and vitronectin, are present on human spermatozoa. Fresh ejaculate spermatozoa and capacitated spermatozoa, before and after a calcium ionophore (A23187)-induced acrosome reaction, were either fixed and their reaction with anti-integrin monoclonal antibodies detected by immunoperoxidase staining or studied without fixation, using cytofluorimetric scanning. Expression of specific integrin chains varied with the functional state of spermatozoa. The α5 chain was not detected on fresh living spermatozoa, but was present on capacitated spermatozoa, whether fixed or living. The pattern of fa expression on living spermatozoa paralleled that of α5. No further increase in the expression of either α5 or β1 was observed following an ionophore-promoted acrosome reaction. In contrast, αv was detected on neither fresh, living ejaculate spermatozoa, nor following capacitation (v positive cells increased substantially following ionophore exposure. Expression of α3 was similar to αv, and the percentage of cells displaying β3 correlated with the proportion of spermatozoa that had undergone an acrosome reaction, following ionophore exposure. These results indicate that the expression of integrins on spermatozoa is dynamic, varying with their functional state and that integrin receptors for fibronectin (α5β1) become apparent on the spermatozoan surface during capacitation and vitronectin (αvβ3) following the acrosome reaction.

This publication has 0 references indexed in Scilit: