Monoclonal antibody 9.3 and anti-CD11 antibodies define reciprocal subsets of lymphocytes.

We have previously described antibody 9.3 which recognizes a 44-kDa polypeptide designated Tp44 expressed on 70-80% of peripheral blood T cells, including nearly all CD4+ cells and some CD8+ cells. Whereas the 9.3+ population contains helper cells, cytotoxic T cell precursors and cytotoxic T cell effectors, the 9.3- population has been reported in several models to contain precursors for suppressor cells. In this report, we demonstrate that 9.3- lymphocytes express CD11, an antigen which is also present on monocytes and granulocytes. Among lymphoid cells, Tp44 and CD11 represent markers that identify reciprocal, nonoverlapping subsets, each of which contains both CD8+ cells and CD4+ cells. With Tp44 and CD11, and CD4 and CD8, the development and function of T cells can thus be examined within the framework of two distinct systems of reciprocally expressed antigens.