The antigens participating in the macrophage micration inhibition to Mycoplasma pneumoniae.

Recently the association of cellular immunity with pulmonary infiltrates in Mycoplasma pneumoniae infection has been suggested. Guinea pigs infected experimentally with M. pneumoniae developed a cellular hypersensitivity that could be demonstrated in vitro by the macrohage migration inhibition test. Peritoneal exudate cells obtained from guinea pigs sensitized with the organism were inhibited from migrating out of capillary tubes by the whole cell antigen. When the whole cells were extracted with aqueous acetone, the activity was found in the acetone insoluble (lipid-depleted) fraction, but not in lipid fraction. The activity was heat resistant, but diminished by treatment of 0.8 N HC1 at 100 degrees C for 30 min. The antigens responsible for the cellular immunity of M. pneumoniae were separated from the lipid, which had been considered the specific hapten associated with humoral immunity to this organism.