cell surface glycoproteins of murine cytotoxic T lymphocytes. I. T 145, a new cell surface glycoprotein selectively expressed on Ly 1-2(+) cytotoxic T lymphocytes

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Abstract
T [thymus-derived] lymphocytes at various stages of maturation and differentiation were isolated by cellular fractionation procedures and characterized by cell surface markers and functional assays. The cell surface glycoproteins of the various T-cell preparations were selectively radiolabeled by the galactose oxidase-tritiated sodium borohydride technique and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. Details were presented on the appearance of a new cell surface glycoprotein (T 145), present on immunocompetent T lymphocytes after activation by major histocompatibility complex alloantigens or by concanavalin A. The intensity of T 145 expression on T lymphoblasts was directly correlated in time and extent to the levels of cytotoxicity generated in a variety of T-cell activations. Specific enrichment procedures of purified populations of mixed leukocyte culture blasts demonstrated that Ly 1+2- blasts are T 145- and Ly 1-2+ blasts are strongly T 145+. Similar enrichment procedures on normal peripheral T cells failed to reveal any significant expression of T 145 on a highly enriched population of Ly 1-2+ T cells. Further studies on the stability of T 145 expression after induction demonstrated that it is a more permanent-type differentiation structure whose expression is clearly not linked to the blast stage of activation. T 145 probably represents a membrane glycoprotein whose exclusive expression on T lymphoblasts is further restricted to a defined group of cells endowed with cytolytic activity and bearing the Ly phenotype Ly 1-2+.