title: Distinction of virgin and memory T lymphocytes. Stable acquisition of the Pgp-1 glycoprotein concomitant with antigenic stimulation.
abstract: The Pgp-1 glycoprotein was identified on a minor (27%) subset of peripheral Lyt-2+ or L3T4+ T cells. In contrast, mature medullary-type thymocytes (Lyt-2+ L3T4-, Lyt-2- L3T4+) were nearly devoid of cells expressing detectable surface Pgp-1. The appearance of peripheral Pgp-1- T cells was found to be thymus dependent, as demonstrated by the diminished proportion of Pgp-1- T cells after thymectomy and their virtual absence in athymic nude mice. The subsequent acquisition of surface Pgp-1 was found to be a stable differentiation event occurring concomitantly with primary antigenic stimulation; selected Pgp-1- mature T cells from thymus or periphery acquired constitutive expression of Pgp-1 after stimulation in vitro with alloantigen or mitogens. These observations were extended by studies in vivo showing that immunization with various antigens augmented the percentage of Pgp-1+ spleen cells within the Lyt-2+ subset. Furthermore, the frequencies of antigen-specific CTLp, after immunization by any of three different antigens tested, were greatly enriched in the Pgp-1+ compared with the Pgp-1- subpopulations. Peritoneal exudate Lyt-2+ cells, after a localized allograft rejection, demonstrated a particularly prominent Pgp-1+ subpopulation (78%) that contained virtually all the allospecific cytolytic activity. A model consistent with all of these data proposes that mature thymocytes lacking surface Pgp-1 upon emigration to the periphery acquire its expression at the time of primary antigenic stimulation. Hence, expression of Pgp-1 among peripheral T cells is an important differentiation marker for identifying antigen-stimulated memory T cells.
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D002478:Cells, Cultured; D005260:Female; D006023:Glycoproteins / Q000032:analysis*; D007156:Immunologic Memory; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D008819:Mice, Nude; D016201:Receptors, Lymphocyte Homing; D013601:T-Lymphocytes / Q000032:analysis / Q000145:classification* / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000032:analysis; D013950:Thymus Gland / Q000166:cytology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D006023:Glycoproteins; D016201:Receptors, Lymphocyte Homing