Clonal expression of differentiation and Ia-like antigens on alloreactive human T lymphocytes

Abstract

A series of human T lymphocyte clones showing specific responses for major histocompatibility complex-encoded alloantigens were isolated from a single culture. They were classified into distinct functional groups based on measurement of alloantigen-specific proliferation and cytotoxicity. Surface antigen expression on these clones was analyzed using a panel of monoclonal antibodies specific for T cell differentiation antigens and for Ia-like antigens. Four distinct groups were identified based on the Leu series of differentiation antigens: (a) Leu1⁺,2⁺,3⁺,4⁺; (b) Leu1⁺,3⁺,4⁺; (c) Leu1⁺,2⁺,4⁺; and (d) Leu2⁺,4⁺. Functionally distinct clones showed not only differential expression of Leu2 and Leu3, antigens which had previously been shown to distinguish helper/inducer and cytotoxic/suppressor cells, but also of Leu1, an antigen classified as a common T cell marker. All of the clones were found to express Ia antigens as detected by three framework monoclonal antibodies, but none were found to express a determinant associated with the DR3 allospecificity, although it was found on normal B lymphocytes and a B cell line established from the HLA-DR3 individual from whom these clones were derived.