Involvement of the macrophage mannose-6-phosphate receptor in the recognition of Leishmania mexicana amazonensis.

Significant differences were found in the ability of resident mouse peritoneal macrophages to ingest amastigote and promastigote forms of Leishmania mexicana amazonensis. Differences in the association index of the parasites to the macrophages were also found between infective and non-infective promastigotes. Evidence was obtained suggesting that the macrophage receptor, which recognizes mannose-6-phosphate-containing units found in lysosomal enzymes, is involved in the association with the macrophage of promastigotes, but not of amastigotes. Addition of mannose-6-phosphate, its structural analogue fructose-1-phosphate, Hansenula holstii phosphomannan or the mannose-6-phosphate-containing lysosomal enzyme alpha-D-mannosidase to the interaction medium, markedly inhibits the association of the parasites with macrophages.