Passive immunization with anti-laminin immunoglobulin G modifies the integrity of the seminiferous epithelium and induces arrest of spermatogenesis in the guinea pig

In the testis, the base of the Sertoli cells is in contact with the basemen t membrane matrix, in which the laminins constitute the major noncollagenou s components. We have previously demonstrated that antibodies against a pre paration enriched in basement membranes of seminiferous tubules (STBM) or a noncollagenous fraction of STEM passively transferred induced modification s to the basement membranes and focal sloughing of the seminiferous epithel ium in the rat. In the present report, we tested the effect of passive immu nization with anti-laminin IgG on the limiting membrane of the seminiferous tubules, spermatogenesis, and maintenance of the blood-testis barrier in t he adult guinea pig. Rabbit antibodies to laminin a (IgG fraction) were inj ected in adult male guinea pigs (GP). Nonimmunized GP and GP immunized with normal rabbit serum IgG were used as controls. Measurements of variations in the diameter and lumen of the tubules and in the size of individual comp onents of the tubular limiting membrane showed that the highest percentage of tubules with reduced lumen occurred 30 days after passive immunization w ith anti-laminin, when the limiting membrane was thickest and lesions to th e seminiferous epithelium were most severe. The lesions included thickening of the limiting membrane, infolding in the basal lamina, deposits of immun e complexes coincident with sloughing of pachytene spermatocytes and sperma tids, and vacuolization of the Sertoli cells. Mononuclear cell infiltration of the tubules was rare. Permeability tracer studies revealed that Sertoli cell fight junctions remained impermeable. Fifty and 80 days after treatme nt, the basement membrane of the tubules and the progression of the spermat ogenesis were normal. Passive immunization with antilaminin IgC provided a valuable experimental model for the in vivo study of the influence of the b asement membrane on the issue of spermatogenesis and the integrity of the s eminiferous epithelium.