title: Interleukin-2 and serum thymic factor enable autologous rosette-forming T lymphocytes to generate helper and cytotoxic functions.
abstract: The autologous rosette-forming T cells (Tar cells) isolated by means of their ability to form rosettes with autologous erythrocytes were characterized by the use of OKT monoclonal anti-human T-cell subset antibodies and a monoclonal anti-HLA-DR antibody. We found that the phenotype of Tar cells was OKT 3+4+8+Dr- as determined by both indirect immunofluorescence microscopy and complement-mediated killing of 51Cr-labelled Tar cells. In addition, we found that Tar lymphocytes were able to develop cytotoxicity against allogeneic and trinitrophenol (TNP)-conjugated autologous target cells in the presence of interleukin-2 (IL-2) or serum thymic factor. However, these cells showed little or nor cytotoxicity in the absence of interleukin-2 or serum thymic factor. Tar lymphocytes generated helper function for B lymphocytes in the presence of interleukin-2 in both pokeweed mitogen (PWM)- and purified protein derivative (PPD)-stimulated cultures. Nevertheless, non-IL-2-treated Tar cells did not exhibit any helper activity on B cells. Finally, pretreatment of Tar cells with 1000-1500 rad of X ray made these cells unable to develop helper function for B lymphocytes. It is concluded that: (1) OKT 3+4+8+Dr- Tar cells are able to generate cytotoxicity against alloantigens and TNP-labelled self structures provided they are stimulated by IL-2 or serum thymic factor; (2) these cells need both to proliferate and to receive help from IL-2 to develop helper cells capable of assisting B-lymphocyte differentiation into plasma cells in both PWM- and PPD-stimulated cultures.
mesh_terms: D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000494:pharmacology*; D008211:Lymphocyte Cooperation / Q000187:drug effects; D008222:Lymphokines / Q000494:pharmacology*; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013935:Thymic Factor, Circulating / Q000494:pharmacology*; D013951:Thymus Hormones / Q000494:pharmacology*
chemical_list: D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D008222:Lymphokines; D013951:Thymus Hormones; D013935:Thymic Factor, Circulating