Monoclonal antibodies against T-cell antigens studied by immunohistochemistry.

Fifteen monoclonal antibodies against different T-cell antigens were studied by immunohistochemistry in thymus, fetal thymus, fetal liver, palatine tonsils, and a few T-cell lymphomas. OKT 9 was identified as reacting with hemopoietic stem or precursor cells in fetal liver as well as with early B-determined lymphocytes in tonsillar germinal centres. OKT 10 labelled lymphocytes in thymus and surprisingly also the cytoplasm of some tonsillar cells with plasma-cell like appearance. OKT 6 and MAS 036 b reacted only with thymic cells. OKT 4, OKT 5, OKT 8,8-11, labelled thymic cells- and portions of interfollicular cells in tonsils. OKT 3, NEI 016, NEI 015, and T 28 stained a majority of thymic cells and of tonsillar interfollicular lymphocytes. IFH-M 203, NEI 012 and 4-11 were positive with the majority of T-lymphocytes in tonsils but labelled only a few thymic cells.