title: Comparative aspects of T cell activation in vivo following stimulation with anti-CD3 MAB, allogeneic cells and Trypanosoma cruzi.
abstract: The in vivo administration of the immunosuppressive drug, Cyclosporin A (CSA), has allowed us to define IL-2 dependent and IL-2 independent pathways of T cell activation in vivo. Thus, CSA inhibited T cell activation and the production of IL-2 mRNA in the draining lymph node (LN) population following footpad injection of anti-CD3 mAb. In contrast, even though CSA completely inhibited the induction of IL-2 mRNA in the draining LN following the injection of allogeneic cells, T cell activation proceeded normally. In the present study, we have analyzed the effects of CSA on the T cell activation induced in vivo by T. cruzi. BALB/c and C57BL/6 mice were injected subcutaneously in the footpad with irradiated, cultured T. cruzi trypomastigotes (CMTs, clone sylvio-X10/4). CSA was delivered to the mice via an osmotic pump, Alzet 2001 at a concentration of 35mg/Kg/day. The injection of CMTs resulted in a dose dependent activation of the draining LN population including an increase in the number of cells, an increase in cell size, induction of expression of the IL-2 receptor and other T cell activation antigens (Ly-6, CD28), induction of responsiveness to IL-2, and a vigorous proliferative response when the freshly explanted node was cultured for 18 h in vitro in the presence of 3H-TdR. CSA markedly inhibited all of these parameters of T cell activation. Thus, the early T cell activation response observed after injection of irradiated T. cruzi CMTs appears to be mediated by an IL-2 dependent, CSA sensitive T cell activation pathway.
authors.affiliation: Cellular Immunology Section, LI-NIAID, Bethesda, MD.
authors.forename: G M
authors.initials: GM
authors.lastname: Pereira
authors.forename: G de C
authors.initials: Gde C
authors.lastname: Furtado
authors.forename: W M
authors.initials: WM
authors.lastname: Yokoyama
authors.forename: T L
authors.initials: TL
authors.lastname: Kipnis
authors.forename: E M
authors.initials: EM
authors.lastname: Shevach
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003524:Cyclosporins / Q000494:pharmacology*; D005260:Female; D008198:Lymph Nodes / Q000187:drug effects / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013601:T-Lymphocytes / Q000187:drug effects / Q000502:physiology*; D014349:Trypanosoma cruzi
chemical_list: D000911:Antibodies, Monoclonal; D003524:Cyclosporins