IMMUNOHISTOCHEMICAL DETECTION OF TETRASPANINS CD81 AND CD9 DISTRIBUTION IN BULL TESTIS AND EPIDIDYMIS

Mammalian spermatozoa, produced by the testes, must undergo maturation in the epididymis to gain the ability to fertilize an ovum. This process includes structural modifications, such as changes in the lipid and protein composition of the plasma membrane. The CD81 and CD9 proteins, which are members of tetraspanin superfamily, have been found to be involved in the fertilization process. Our study examined the presence of CD81 in the bull testis and epididymis, and then compared CD81' s distribution profile with that of the molecule CD9. We detected CD81 in the basement membrane along the whole epididymis. In comparison, an abundant expression of CD9 molecule was found in the testis as well as in all three segments of the epididymis. Both molecules are part of the tetraspanin web, and are considered key elements in the sperm-egg interaction.