Two kinds of hybridoma clones, one producing monoclonal antibodies against Sertoli cell (TM-1) and the other the basal lamina of the seminiferous tubule (TM-2), were raised by fusion between P3X63Ag8-653 mouse myeloma cells and spleen cells of BALB/c mice (H-2d) immunized with testicular homogenate of the same inbred mice. Immunohistochemically, TM-1 reacted specifically with cytoplasmic component of Sertoli cell and TM-2 with basal lamina of the seminiferous tubule. Using these monoclonal antibodies, spermatogenic disturbance was induced experimentally in BDF1 (H-2b/d) by intratesticular injection of a set of these two antibodies. Single injection of either TM-1 or TM-2 failed to induce the lesion. This fact indicated that TM-1 antibody could reach the Sertoli cell to impair its function, which was otherwise inaccessible without coincidental action of TM-2 antibody. TM-2 antibody appeared to alter the permeability of the basal lamina of the tubule and lower its barrier effect.