Differential labeling of the pinealocytes and pineal interstitial cells by a series of monoclonal antibodies to human pineal body.

Ten hybridomas producing monoclonal antibodies against pineal antigens were established by hybridizing mouse myeloma cells with spleen cells from BALB/c mice immunized with human pineal body homogenate. Seven antibodies immunohistochemically reacted with the pinealocytes and three reacted with the pineal interstitial cells. According to the antibodies applied, the pinealocytes were immunostained in a variable manner; granularly with PP1, PP4 and PP6 antibodies, diffusely with PP2 and PP5, membraneously with PP3, and apically with PP7. The PI1 and P12 antibodies immunolabeled most of the interstitial cells, but PX1 immunolabeled only a small population of these cells. An immunoblotting study indicated that single or multiple polypeptides of the pineal homogenate constituted the antigen epitopes for these antibodies. Most antibodies also immunoreacted with several cell types of the extra-pineal tissues, thus these antibodies are not specific to the human pineal body. This series of monoclonal antibodies should be available for immunohistochemical studies involving the normal and pathological human pineal body.