T cell activation via CD2 [T, gp50] molecules: accessory cells are required to trigger T cell activation via CD2-D66 plus CD2-9.6/T11(1) epitopes.
Binding monoclonal antibodies (MAb) both to D66 and 9.6/T11(1) epitopes on the CD2 [T,gp50]-defined molecule produces a high level of T cell mitosis. This was observed with a battery of MAb of different isotypes. In contrast, none of the anti-D66 or anti-9.6/T11(1)Ab could trigger T cell proliferation in combination with anti-T11(3). Moreover, all anti-D66-9.6/T11(1) 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/T11(1) pairs of Ab, 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/T11(1) Ab. The addition of exogeneous IL 2 could overcome the removal of accessory cells or the modulation of CD3 molecules. In contrast, 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/T11(1) 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.
P
P
Brottier
L
L
Boumsell
C
C
Gelin
A
A
Bernard
D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes; D006801:Humans; D007152:Immunologic Capping; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation; D008938:Mitosis; D009000:Monocytes / Q000276:immunology*; D011971:Receptors, Immunologic / Q000276:immunology; D015375:Receptors, Interleukin-2; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000939:Epitopes; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2