Comparative expression of T9, T10, and Ia antigens on activated human T cell subsets

In the present study, the expression of three surface molecules T9, T10, and Ia, which are found on activated T lymphocytes, was examined utilizing monoclonal antibodies and indirect immunofluorescence. These antigens were shown to appear on T lymphocytes in a defined temporal sequence which was dependent on the specific triggering stimulus. Moreover, when T cells were fractionated into individual subsets of T4+ inducer and T8+ cytotoxic/suppressor lymphocytes, the expression of all three molecules was restricted to the T4+ subset following soluble antigen stimulation. By contrast, both subsets expressed these surface determinants following mitogen or alloantigen stimulation. The above results suggest that there may be successive stages in the T cell activation process associated with the appearance of unique cell surface antigens and further support the view that various triggering stimuli activate T cell populations differently.