Isolation and immunocytochemical characterization of a library of monoclonal antibodies directed against rat testicular antigens.

OBJECTIVE To characterize immunocytochemically the antigens recognized by monoclonal antibodies (Mabs) in the library we have accumulated and to reveal their spatiotemporal distribution in testicular tissue in the course of testis development. METHODS Female BALB/c 2-month-old mice were immunized intraperitoneally with isolated immature Sertoli and germ cells obtained from 20 day old male Wistar rats. The obtained Mabs were characterized by its cell type-specific binding reaction using light immunocytochemistry (avidin-biotin-peroxidase complex technique, immunogold-silver staining, indirect immunofluorescence). RESULTS On the basis of immunocystochemical results the selected Mabs were divided into four classes: 1. Mabs of class 1 recognized the differentiation specific antigens appearing during germ cell development, two of them revealing a stage-specific expression of nuclear antigens from preleptotene to early pachytene stage. Other Mabs of this class 1 detected the antigens in pachytene spermatocytes and acrosomes of round spermatids until their elongation; 2. the labeling of class 2 Mab was restricted only to Sertoli cell cytoplasm; 3. the binding of class 3 Mabs was observed in the cytoplasm of germ and Sertoli cells; 4. Mabs of class 4 reacted with antigens distributed in the cytoplasm of primary spermatocytes, Sertoli and Leydig cells. CONCLUSIONS The Mabs from the library we have accumulated recognized the antigens in different cell types at various stages of testicular development and could be an useful tool for the characterization of cell- and development- specific molecules which may participate in germ cell differentiation and/or cell to cell interactions during testis development.