Pharmacological modification of immunoregulatory T lymphocytes . II. Modulation of T lymphocyte cell surface characteristics.

Human peripheral blood lymphocytes were fractionated into non-T lymphocyte, T lymphocyte, theophylline resistant (TR) and theophylline sensitive (Ts) T lymphocyte subpopulations. The proportion of cells bearing surface membrane immunoglobulin (sIg), Clq, Ia antigen, beta 2 microglobulin and T lymphocyte specific antigens detected by monoclonal antibodies OKT3, OKT4, OKT5 and OKT8 was studied using immunofluorescent techniques. Incubation of T lymphocytes or TR lymphocytes with adenosine or impromidine, an H2 histamine agonist, under conditions previously shown to increase Fc gamma receptors and radioresistant suppressor cell activity, was found to increase the proportion of cells expressing readily detectable surface beta 2 microglobulin and the antigen detected by OKT8. Cells expressing OKT4 antigen declined and there was no change in OKT3, OKT5, Ia, Clq, sIg or Es receptor expression. These data indicate that the expression of T lymphocyte Fc gamma receptors, beta 2 microglobulin and the antigens detected by the monoclonal antibodies OKT4 and OKT8 are, at least in part, regulated by agents acting upon adenosine and H2 histamine receptors.