Amoebiasis, caused by an enteric protozoanEntamoeba histolytica, is one of the major
parasitic diseases of mankind. Current estimate suggests that the parasite infects about 10% of the world population at any given time. There is an urgent need to characterize the antigenic molecules ofE. histolytica, and find out
antigens which have both immunodiagnostic and prophylactic potential against
amoebiasis. The results of somatic
antigen analysis, using sera from immune or infected individuals, indicated that the wholeE. histolytica trophozoites, are highly complex and heterogeneous in nature and both immunodiagnostic and immuno prophylaxis activity remain mainly in a surface associated 29 kDa
glycoprotein ofE. histolytica. Future studies at molecular level particularly, genes responsible for expression of this
protein, their homology with other
proteins and structure analysis will give better understanding about this
polypeptide. Studies on excretory secretory
antigens, clearly demonstrated thatE. histolytica like many organisms, also liberates certain antigenic moieties into the culture medium during in vitro cultivation and this
antigen has similar diagnostic values like the conventional somatic
antigens. It is important that the ESA should be prepared from the supernatant after collecting the cell and use for immunodiagnosis of
amoebiasis. This is an additional source of
antigen which will help in carrying out more tests using the same
reagents. Further studies are needed to clarify the location of these molecules on the parasite, along with detailed biochemical and immunological characterization and their relation with the pathogenesis.