Expression of a 26,000-dalton glycoprotein on activated human T cells

In the present study, we describe the expression of a 26,000-dalton glycoprotein on human T cells following stimulation by either mitogen or alloantigen. This glycoprotein, which is the target antigen of a monoclonal antibody designated J2, is distinct from Ia-like molecules and is not present on resting T cells. We demonstrate GP 26 expression in both major immunoregulatory subsets i.e., T4⁺ (inducer) and T8⁺ (cytotoxic/suppressor) following activation and show that the GP 26-bearing cells are not directly responsible for the cytotoxicity generated in MLR. The relationship of the J2 target antigen to other glycoproteins with similar molecular weight which have been described on activated T cells is discussed.