Cell surface lipophosphoglycan of Leishmania donovani

Based on a galactose oxidase/NaB[3H]4 technique of radiolabeling macromolecules, the major glycoconjugate (lipophosphoglycan) of Leishmania donovani promastigotes was determined to be located on the cell surface. Incorporated radioactivity was analyzed by gel filtration on Sephadex G-100, chromatography on ricin agglutinin-coupled agarose, and lability to mild acid hydrolysis. Lipophosphoglycan was present throughout the various phases of growth of promastigotes, but was preferentially expressed during the latter part of logarithmic phase and in the stationary phase. In addition, metabolically labeled lipophosphoglycan was released into the culture medium. Expression of this unusual glycoconjugate on the cell surface of L. donovani suggests that it may play a major role in host cell-parasite interactions.