Regulation of the human allogeneic proliferative response in vitro.

We have investigated the glass-wool-adherent characteristics of human lymphocytes able to suppress allogeneic proliferation in vitro. We observed that: (1) Suppressor cells obtained after in vitro priming and their precursors are adherent to glass wool, whereas cytotoxic cells and their precursors are not; (2) primed cells adherent to glass wool are mainly HLA-DR positive, while nonadherent cells are HLA-DR negative or weakly positive; (3) the nonadherent, unprimed T cells used as responder cells in a primary MLR are more readily suppressed by suppressor cells than the same cells unfiltered. This may suggest an enrichment of 'acceptor' cells for suppression.