Adenosine A2A receptor stimulation does not directly impair Tc1 or Tc2 cell cytolytic capacity. (A) Heteroconjugate assay reflective of granule exocytosis mediated cytolysis. 51Cr lysis assay was performed by incubating effector Tc1 and Tc2 cells (day 6 of culture) with P815 target cells in calcium replete media, with effector and target cell recognition mediated by anti-CD3 antibody (clone 2C11). Experimental groups included CGS (10-8 and 10-6 M; ▴ and ×, respectively); the control effector group was evaluated in DMSO vehicle (▪). An additional control group did not receive anti-CD3 (♦). E/T ratio indicates effector-target ratio. (B) Cytolysis via fas ligand. Fas ligand on Tc1 and Tc2 cells was induced with PMA and calcium ionophore, and cells were evaluated in 51Cr assays using wild-type (L1210) or fas-transfected (L1210-fas) targets in Ca++-neutralized conditions. Tc1 and Tc2 effectors were incubated with CGS (10-8 and 10-6 M; ▴ and ×, respectively), or with vehicle control (DMSO; ▪); an additional control consisted of DMSO-treated Tc1 and Tc2 effectors and the nontransfected L1210 cell line as target (♦).
