Production of a suppressor factor by adherent cells from Mycobacterium tuberculosis-infected guinea-pigs.

Adherent cells from the spleen of guinea-pigs infected with Mycobacterium tuberculosis (M. tuberculosis) spontaneously released a factor which suppressed the blastogenic response of normal guinea-pig and human peripheral blood lymphocytes to PHA activation. Suppressor factor production was evident within 3 hr of culture, continued for 2 days and diminished thereafter. This effect was not observed in supernatants derived from normal guinea-pig splenic adherent cells or from peripheral blood adherent cells of both normal or M. tuberculosis-infected guinea-pigs. Analysis of the spontaneously generated adherent cell supernatant indicated that it activated a subpopulation of lymphocytes to become suppressor cells. We conclude that adherent cells phagocytosing M. tuberculosis at the site of the lesion release a factor which activates suppressor cells, and that these cells may be important in the cellular unresponsiveness which develops in animals or man with advanced tuberculosis.