The study of the acid phosphatase of macrophagal lysosomes in delayed-type hypersensitivity

Abstract

The acid phosphatase (APh) has been studied, using various techniques, in peritoneal macrophage cultures from guinea-pigs, normal and sensitized with group A streptococci or BCG.

The proportion of cells in which the acid phosphatase (APh) is determined histochemically, without preliminary fixation of cells, is increased as a result of the action of the specific antigen on macrophage cultures prepared from animals with delayed-type hypersensitivity (DTH). The increase is immunologically specific, since it is not evoked by antigens to which the animal is not sensitized. The described action of the specific antigen on cells in DTH is not dependent on increased amounts of APh and, apparently, is related to increased membrane permeability. The latter facilitates penetration of the substrate, used in APh determination, into lysosomes. Suppression of the effect of the specific antigen on cells with dexamethasone supports this suggestion. Increased membrane permeability, resulting from the action of the specific antigen on macrophages in DTH, should probably promote penetration into the tissues of lysosomal enzymes. The latter might result in tissue damage due to the action of the lysosomal enzymes.