Objective: To define the involvement of Sertoli cells in immune suppression within the testis by identifying surface receptor molecules that describe or communicate with cells of the immune system.
Materials and methods: Ten pairs of human testes obtained from orchidectomy were stained immunohistochemically with established monoclonal antibodies that identify common cells of the immune system.
Results: Patterns of staining were similar in all testes. Class I major histocompatibility complex (MHC) antigen, important for self/non-self recognition, was found on Sertoli cells. Class II MHC antigen, important for immune cell interaction and limited to immune cells, was absent. Leu M3, characteristically found on macrophages, was also seen on Sertoli cells but no receptor antigens defining basic T cell types (CD4, CD8), B cells (Leu 12) or natural killer cells (Leu 11) were seen on Sertoli cells.
Conclusions: The Sertoli cell membrane lacks lymphocyte-cell surface markers but harbours somatic cell and macrophage markers. This suggests that immunosuppression within the testis is not maintained through classic lymphocyte receptors. The presence of a macrophage marker is consistent with the known phagocytic activity of the Sertoli cell.