Studies of the nature of extracellular components of rat seminiferous tubular wall. II. Immunological characterization of basement membrane antigen.

An antiserum was obtained in rabbits using as antigen a preparation rich in basement membranes isolated from normal rat testis. By passive hemagglutination test a titer of 1/20,000 was obtained when the antiserum was reacted with the specific antigen; no cross reactions were detected with other fractions extracted from the germinal cells of rat testis. A weak cross reaction was obtained when the antiserum was reacted with collagen extracted from rat testis. Moreover, the antiserum cross reacted with other isolated basement membranes such as glomerular basement membrane of rat kidney and sheep lens capsule. By the indirect immunofluorescent technique the localization of the antigen antibody reaction was detected at the seminiferous tubular wall and vessels. No reaction was observed in other structures of the testis except for a faint reaction at the interstitial collagen fibers. Both, serological and immunohistochemical techniques demonstrated: (1) the existence of common antigenic determinants among basement membranes of different organs of the rat, (2) a partial immunological identity among basement membranes of different species.