Activation of purified human T cells by mitogens: diminished mitogen-induced deoxyribonucleic acid synthesis in human T cells compared with autologous peripheral blood lymphocytes.
Human thymus-derived (T) cells were isolated from peripheral blood after rosette formation with neuraminidase-treated sheep erythrocytes (SRBC). After separation on Ficoll-hypaque, SRBC were removed from T cells by treatment with tris(hydroxymethyl)aminomethane-NH4Cl. Human T cells and autologous peripheral blood lymphocytes (PBL) were then incubated with phytohemagglutinin, concanavalin A, or pokeweed mitogen. Human T cells, in the absence of other cell types, responded with less deoxyribonucleic acid (DNA) synthesis (measured by uptake of [3H]thymidine) than equal numbers of autologous PBL. Further experimentation established that, compared with autologous PBL, the diminished capacity of human T cells to be activated by mitogens was due neither to differences in the mitogen dose-response relationship nor to the time of peak DNA synthesis of T cells or autologous PBL. Fragments or components of SRBC were not detected on human T cells, and treatment of the T cell-SRBC mixture with tris(hydroxymethyl)aminomethane-NH4Cl did not contribute to the results. Increased cell density or a period of preculture before addition of mitogen also did not influence the degree of decreased DNA synthesis in human T cells compared with the response of autologous PBL incubated with the same mitogens. When mixed with the cells remaining at the Ficoll-media interface, purified human T cells did not suppress the mitogenic response of this cell mixture to PHA or concanavalin A. The data indicated that human T cells, in the absence of other cell types, were activated by mitogens to a lesser degree than autologous PBL. Furthermore, T cells responded with DNA synthesis after direct T cell-mitogen interaction.
D002469:Cell Separation; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D007104:Immune Adherence Reaction; D037102:Lectins / Q000494:pharmacology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D008934:Mitogens / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology*
D037102:Lectins; D008934:Mitogens; D003208:Concanavalin A; D004247:DNA