Evidence for the existence of ganglioside molecules in the antigen of Entamoeba histolytica

Abstract

Gangliosides were found to be present in Entamoeba histolytica. They were extracted from lyophilized trophozoites of the pathogenic strain HM-1:IMSS and purified by high performance thin-layer chromatography. Two resorcinol-positive bands, comigrating with GM2 and GD1a were demonstrated, revealing the existence of ganglioside molecules in Entamoeba histolytica. The GM2 content, determined as lipid-bound sialic acid, was 1.5 micrograms/10(8) amoebae, the content of the GD1a comigrating band was 0.32 microgram/10(8) amoebae. The identity of the GM2 comigrating band was confirmed by TLC immunostaining, using the monoclonal anti-GM2 antibody GMB28. Furthermore, six out of ten anti-amoeba positive sera selectively reacted with the GM2 comigrating band, as revealed by immunostaining on TLC plates. Absorption tests revealed that preincubation of anti-amoeba positive sera with standard GM2 was followed by a significant decrease in the reaction with amoeba trophozoites by indirect immunofluorescence. These results demonstrate that a GM2 comigrating component of Entamoeba histolytica may be one of the antigens responsible for the appearance of circulating antibodies in patients with amoebiasis.

Dietary lipids containing gangliosides reduceGiardia murisinfectionin vivoand survival ofGiardia lambliatrophozoitesin vitro

“…This suggests that host lipids play a critical role in metabolism and long-term survival of the parasite. Gangliosides, GM2 and GD1a, have been identified as membrane components of another gastrointestinal parasite, Entamoeba histolytica (Sorice et al 1996). It is possible that the exogenous gangliosides are taken up by trophozoites which could affect the ganglioside composition in the trophozoite cell membrane and disturb the structural components of the trophozoites, leading to lysis of the parasite.…”

Chemical Diversity in the Sialic Acids and Related α-Keto Acids: An Evolutionary Perspective

“…The sialic acids are thought to protect these organisms from detection and attack by host immune system . There are some studies claiming the presence of sialic acids (Neu5Ac, Neu5Gc, Neu5,7Ac 2 , and Neu5,9Ac 2 ) on other protozoal cells, such as a slime mold Dictyostelium discoideum , a trypanosome Crithidia fasciculata , a piroplasmid Theileria sergenti , and the amoebae Entamoeba invadens and E. histolytica . , Whether these organisms synthesize sialic acids on their own is an unsolved question. There is insufficient genomic data on these organisms to allow a search for genes known to be involved in the biosynthesis, activation, or transfer of sialic acids.…”

Sialic acid and biology of life: An introduction

“…These sialic acids might play a role in conferring protection from the recognition and response by the host immune system. Sialic acid such as Neu5Ac, Neu5Gc, Neu5,7Ac2, and Neu5,9Ac2 have been reported to occur in Dictyostelium discoideum, a trypanosome Crithidia fasciculata (C. fasciculata), piroplasmid Theileria sergenti (T. sergenti), and amoebae Entamoeba invadens (E. invadens) and Entameoba histolytica (E. histolytica) [6,[181][182][183][184][185].…”