T-CELL ACTIVATION VIA CD2 [T,GP50] MOLECULES - ACCESSORY CELLS ARE REQUIRED TO TRIGGER T-CELL ACTIVATION VIA CD2-D66 PLUS CD2-9.6/T111 EPITOPES

  • 1 January 1985
    • journal article
    • research article
    • Vol. 135  (3) , 1624-1631
Abstract
Binding monoclonal antibodies (MAb) both to D66 and 9.6/T111 epitopes on the CD2 [T,gp50]-defined molecule produces a high level of human T cell mitosis. This was observed with a battery of MAb of different isotypes. None of the anti-D66 or anti-9.6/T111 Ab could trigger T cell proliferation in combination with anti-T113. All anti-D66-9.6/T111 pairs of MAb tested required monocytes to activate T cells which were recruited through their Fc receptors. Variations among normal individuals were observed in the level of response to anti-D66-9.6/T111 pairs of Ab (antibody), 75% of a population of French Caucasians giving a high response. The level of response of a given individual was determined by his accessory cells. However, the level of response of an individual appeared to be minimally influenced by the isotype of a peculiar anti-D66 or anti-9.6/T111 Ab. The addition of exogeneous IL 2 (interleukin 2) could overcome the removal of accessory cells or the modulation of CD3 molecules. IL 2 receptor appearance was not overcome by removal of monocytes. Thus, T cell activation via CD2 seems to be produced by touching several definite regions of this molecule which trigger a cascade of events similar to those produced by mitogenic lectins. One can assume that the appropriate conformational changes of the CD2 molecule induced by anti-D66-9.6/T111 pairs of Ab are solely produced when they are presented by accessory cells. This leaves open the question of whether accessory cells would also play a more active role.

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