Human T-cell leukemia virus type I-induced proliferation of human thymocytes requires the presence of a comitogen.
HTLV-I has recently been shown to be a direct activator of resting human peripheral T cells. In order to determine the susceptibility of T-cell precursors to HTLV-I mitogenic activity we have exposed human thymic T cells to uv-inactivated HTLV-I. Unlike mature T cells, thymocytes were not directly susceptible to HTLV-I-induced activation although agglutination of cells did occur after exposure to HTLV-I alone. However, in the presence of another stimulus, phyto-hemagglutinin or anti-CD3 monoclonal antibodies and accessory cells, thymocytes proliferated when exposed to HTLV-I. Concanavalin A did not induce HTLV-I comitogenic activity. HTLV-I-induced thymocyte proliferation was enhanced by autologous or heterologous accessory cells. This proliferation was shown to be mediated by the interleukin-2/interleukin-2 receptor pathway. Simultaneous stimulation by HTLV-I and nonmitogenic doses of phytohemagglutinin were required both for the production of interleukin-2 and for the expression of the interleukin-2 receptor. These data demonstrated functional differences between peripheral T cells and thymocytes.
Dumontet
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INSERM U 218, Centre Léon Bérard, Lyon, France.
Dodon
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Gazzolo
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Gerlier
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D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D000938:Antigen-Presenting Cells; D002449:Cell Aggregation; D002472:Cell Transformation, Viral; D017977:Deltaretrovirus / Q000276:immunology*; D006801:Humans; D007223:Infant; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D008213:Lymphocyte Activation; D051379:Mice; D008934:Mitogens / Q000276:immunology* / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology
D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D008934:Mitogens; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2