The surface phenotype of activated T lymphocytes.
The surface phenotype of T cells reflects both their relative maturity and their activation state. To determine the pattern of surface markers characteristic of activated T cells, purified mature T cells were stimulated in vitro for periods of 0.5-5 days with Concanavalin-A (Con-A) or phorbol myristic acetate (PMA) and ionomycin, fluorescein-labelled with monoclonal antibodies, then analysed by flow cytometry. The level of expression of the function-associated antigens CD4 (L3T4) and CD8 (Ly-2) decreased transiently early after activation with PMA/ionomycin, but not after stimulation with Con-A. Both stimuli caused a small drop in the level of CD3 and the T cell antigen receptor (TCR). At no time was CD3, CD4 or CD8 completely lost from the surface. Following activation Pgp-1, the interleukin-2 (IL-2) receptor (as detected by the monoclonal antibody 7D4) and the peanut agglutinin (PNA) receptor were gained by a proportion of cells, MEL-14 was lost by a proportion of cells, and no change was observed in the expression of heat stable antigen. Thy-1 or Ly-1. From the present data no evidence has been found for the generation of the 'immature', CD4- CD8- phenotype found in the thymus by activation of mature T cells. During T cell development, however, changes in expression of Pgp-1, MEL-14, the IL-2 receptor and the PNA receptor may be associated with activation, rather than differentiation per se.
Kelly
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K
Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia.
Shortman
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Scollay
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R
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D017252:CD3 Complex; D015704:CD4 Antigens / Q000378:metabolism; D016827:CD8 Antigens; D005434:Flow Cytometry; D008213:Lymphocyte Activation; D051379:Mice; D008808:Mice, Inbred CBA; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell; D016201:Receptors, Lymphocyte Homing