Suppression of mitogen-induced proliferation of normal spleen cells by macrophages from chickens inoculated with Marek's disease virus.

Spleen cells from chickens 7 days after inoculation with Marek's disease virus (MDV) responded poorly to stimulation by phytohemagglutinin (PHA). Addition of these cells to syngeneic normal spleen cells caused of marked suppression of the PHA response of the normal cells. The MDV spleen cells also inhibited the DNA synthesis of MSB-1 lymphoblastoid cells in vitro. The suppressive activity is attributed to the presence in MDV spleen cells of a population of suppressor cells with characteristics typical of macrophages. The suppressor cell activity was not removable by treatment with anti-T or anti-B serum with C, but it was reversible by treatment with carrageenan or carbonyl iron/magnet, by passage through glass wool column, and by adherence to plastic Petri dishes. The adherent MDV spleen cells also showed strong suppressor cell activity against syngeneic normal spleen cells.