VIRULENT AND AVIRULENT ENTAMOEBA-HISTOLYTICA AND E-DISPAR DIFFER IN THEIR CELL-SURFACE PHOSPHORYLATED GLYCOLIPIDS

Virulent strains of Entamoeba histolytica have been reported to produc e a mixture of phosphoglycoconjugates that share some structural featu res with the lipophosphoglycans (LPGs) of Leishmania. Purification of these glycoconjugates is essential to their precise structural charact erization. In this study ave have extracted 'LPG-like' molecules from various virulent E. histolytica strains and purified on the basis of c harge differences, 2 apparently related glycoconjugates a 'LPG' and a 'lipophosphopeptidoglycan (LPPG)'. In marked contrast to the abundance of these 'LPG' and 'LPPG' molecules in the virulent strains, avirulen t E. histolytica and E. dispar strains produce either very low, or no detectable levels of LPG, and either low levels or modified forms of ' LPPG'. Monospecific polyclonal antibodies prepared against that 'LPG' of the virulent strain HM-1 : IMSS c16 identified epitopes shared betw een both the 'LPG' and the 'LPPG' of this and other virulent strains, using Western blot analysis. Flow cytometric analysis of a range of st rains using these antibodies identified a surface distribution of thes e molecules and confirmed a correlation between surface exposure of ep itopes bound by these antibodies and parasite virulence.