Characterization of responding cells in oxidative mitogen stimulation. II. Identification of an Ia-bearing adherent accessory cell.

Treatment of murine lymph node or spleen cells with anti-Ia serum and complement (C), depletes the subsequent proliferative response of the residual cells to the oxidative mitogen galactose oxidase (NaGO). Restoration of the mitogenic response could be achieved by the addition of adherent accessory cells prepared by a variety of techniques. Loosely adherent dendritic cells were the most efficient population of restoring cells. Treatment of adherent cells with anti-Ia serum and C removed their capacity for restoration. Restoration of the oxidative mitogen response to lymph node cells depeleted of adherent cells by passage over nylon wool and Sephadex columns was similar to restoration of Ia- depleted lymphocyte populations. Further NaGO-induced lymphocyte transformation requires an Ly-1+2+ T lymphocyte and an Ia-positive adherent accessory cell.