Sertoli cell plasma membrane polypeptides involved in spermatogenic cell-Sertoli cell adhesion

This study concerns Sertoli cell-spermatogenic cell adhesive interactions in the seminiferous tubule. Sertoli cell surface polypeptides involved in germ cell-Sertoli cell adhesion were identified by serological inhibition of an in vitro Sertoli-germ cell adhesion assay. This assay was modified from a previously reported adhesion assay, and employs a scanning laser cytometer for quantification of adherent cells. Reactivity of the polyclonal antiserum raised against rat Sertoli cells was also assessed via immunofluorescent microscopy. The addition of antiserum to the adhesion assay resulted in a 42% to 66% inhibition of cell-cell adhesion. Moreover, preincubation of antiserum with Sertoli cell monolayers resulted in a significant reduction of spermatogenic cell binding. Conversely, preincubation of antiserum with germ cells resulted in no reduction. Western blot analysis of the antiserum against purified Sertoli cell membranes indicated reactivity with four polypeptides. The data suggest that one or more of these polypeptides are directly involved in the adhesion of germ cells to Sertoli cell monolayers in vitro.