GLYCOSPHINGOLIPID ANTIGENS OF LEISHMANIA (LEISHMANIA) AMAZONENSIS AMASTIGOTES IDENTIFIED BY USE OF A MONOCLONAL-ANTIBODY

Monoclonal antibodies directed against Leishmania (Leishmania) amazone nsis amastigotes were produced. One monoclonal antibody (1C3) selected by indirect immunofluorescence reacted with both amastigotes and prom astigotes of L. (L.) amazonensis. Glycolipid extraction from L. (L.) a mazonensis amastigotes and separation by high-performance thin-layer c hromatography followed by immunoblotting demonstrated that 1C3 reacts with two glycosphingolipids which migrate chromatographically similarl y to ceramide-N-acetyl-neuraminic acid (GM1) and ceramide-N-tetrose-di -acetylneuraminic acid (GD1a). The antibody did not react with glycosp hingolipids from L. (L.) amazonensis promastigotes. Immunoprecipitatio n of I-125- and S-35-methionine-labeled promastigotes demonstrated tha t 1C3 recognizes gp63 from L. (L.) amazonensis promastigotes. Biosynth etic incorporation of labeled lipids by L. (L.) amazonensis amastigote s indicated that the glycosphingolipids reactive with 1C3 contain olei c acid in their structures. Surface labeling with galactose oxidase an d sodium boro[H-3]hydride indicated that galactose is present in 1C3-r eactive antigens, strongly suggesting that these glycosphingolipids ar e localized on the surface of L. (L.) amazonensis amastigotes. Inhibit ion experiments of macrophage infection implicated the 1C3-reactive gl ycosphingolipids from L. (L.) amazonensis amastigotes in Leishmania in vasion. The role of gp63 in promastigote-macrophage attachment was als o demonstrated by inhibition experiments performed with 1C3, consisten t with data from the literature.