Expression of carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) in normal human Sertoli cells and its up-regulation in impaired spermatogenesis.

Carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) is usually expressed at the luminal surface of different epithelia and is up-regulated in endothelial cells during angiogenesis. Here, we demonstrate evidence of morphogenetic effects of CEACAM1 in spermatogenesis. CEACAM1 is detectable in normal testicular tissue and seminal fluid. It is present in the adluminal part of Sertoli cells extending only as far as the tight junctions between them. CEACAM1 immunostaining is significantly increased and extends to the basal part of Sertoli cells in the presence of carcinoma in situ. Also, in vitro-induced spermatogenetic disturbance leads to an enhanced CEACAM1 expression in Sertoli cells after 3 days of culture. Remarkably, seminiferous tubules containing exclusively Sertoli cells do not exhibit any CEACAM1 expression. CEACAM1 staining was absent in vascular endothelial cells of normal testicular tissue, but present in small blood vessels of seminomas. These data suggest that CEACAM1 expression in Sertoli cells depends on the presence of germ cells and plays a role in adhesive interactions between Sertoli and differentiating germ cells. Its up-regulation in Sertoli cells accompanying spermatogenic damage may contribute to reconstruction and maintenance of the tubular structure of seminiferous tubules. Additionally, CEACAM1 is apparently involved in the angiogenesis of germ cell tumours.