Characterization of human effector and suppressor T cells by their activity in mixed lymphocyte reaction and by monoclonal antibody phenotyping.

Human T effector and T suppressor cell subpopulations which are functionally operative in the local graft-versus-host reaction were enriched and separated on the basis of their respective ability to form (or not to form) rosettes with sheep red blood cells in the presence of theophylline. These subpopulations were then tested as stimulators and as responders in the allogeneic mixed lymphocyte reaction assay against the same mononuclear cells. Among 18 normal donors, theophylline resistant cells responded more vigorously to mononuclear cells (SI, 9.9 +/- 9.8) than theophylline-sensitive cells (6.7 +/- 5.7, p less than 0.08). In contrast, T-effector cells were poorer stimulators of the same MNC (SI, 4.0 +/- 5.6) when compared to the stimulatory capacity of T suppressor cells (SI, 7.1 +/- 9.8, p less than 0.05). Similar studies among 14 patients with disseminated cancer showed the same, but more pronounced differences. Thus, the theophylline-resistant T effector cells were vigorous responders (SI, 14.7 +/- 10.0) compared to the weak response of the theophylline-sensitive T suppressor cells to the same mononuclear cells (SI, 3.4 +/- 1.8, p less than 0.01). Again, in contrast, T effector cells stimulated mononuclear cells poorly (SI, 1.0 +/- 0.5) while T suppressor cells induced a weak but significant stimulation (SI, 3.2 +/- 2.1, p less than 0.05). Phenotyping of these two functionally distinct subpopulations with monoclonal antibodies to subsets of T cells (Leu I, II, III) and for the HLA-DR antigen (OKIal) showed no enrichment for any of the phenotypes as defined by these antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)