title: Recognition of hapten-modified cells in vitro by human T-lymphocytes.
abstract: Clearer definition of the recognitive structures of human T lymphocytes for antigens will be required to elucidate the molecular basis of diseases and immunological responses induced or regulated by normal or abnormal T-cell function. For this purpose we have investigated the cellular requirements for immune responses in vitro to trinitrophenyl-conjugated peripheral blood mononuclear cells. The responding cell was characterized as a T cell on the basis of rosetting with sheep erythrocytes. T-cell recognition of hapten in proliferative responses depended upon presentation of antigen in an appropriate stimulator-cell context. Neither autologous hapten-modified erythrocytes nor T cells restimulated responses of in vitro-primed lymphocytes. Moreover, hapten-conjugated non-T cells were more effective than modified unfractionated cells in restimulating proliferative responses. Both macrophages and non-T lymphocytes effectively restimulated hapten-conjugate responses.Cell-mixing experiments indicated that the failure of haptenated T cells to stimulate proliferative responses was not because of a lack of fresh macrophages; these experiments suggested instead that T cells do not express appropriate structures necessary to present haptenic determinants in an immunogenic form. Hapten-modified T cells, however, were capable of inducing primed lymphocytes to become efficient cytotoxic effector cells, indicating that T-cell recognitive units for stimulation of proliferative and cytotoxic responses are different. These data support the concept that for induction of proliferative responses, human T cells recognize conventional antigens in association with HLA-D-region-encoded Ia-like molecules.
mesh_terms: D000917:Antibody Formation; D000941:Antigens; D006241:Haptens / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D000941:Antigens; D006241:Haptens; D014301:Trinitrobenzenes