Characterization of entamoeba histolytica antigens in circulating immune complexes in sera of patients with amoebiasis.

Isolated circulating immune complexes (CICs) from sera of patients with amoebiasis were characterized to determine Entamoeba histolytica antigens that participate in the disease process. In total, 116 serum samples were collected before starting anti-amoebic therapy, and their CICs were isolated by differential polyethylene glycol precipitation. The presence of amoeba-specific antigens in CICs was detected by antigen capture enzyme-linked immunosorbent assay (ELISA) and by immunoblot assay. Antigen capture ELISA showed significantly higher optical density (p < 0.001) in all patients with amoebiasis than in the normal healthy controls and patients of non-amoebic hepatic disorder. Immunoblot assay detected amoeba-specific CICs in all 18 patients (100%) with confirmed amoebic liver abscess, 28 (80%) of 35 patients with clinically-suspected amoebic liver abscess, and 18 (78.26%) of 23 patients with amoebic colitis. No patients with non-amoebic hepatic disorders and healthy control subjects had any detectable level of amoebic antigens in CICs. Immunoblot assay revealed E. histolytica antigens of relative molecular masses of 35, 56, 70, and 90 kDa present in CICs of 64 of 76 patients with amoebiasis. The 35-kDa polypeptide was observed in 52 patients (81.25%). The results of the study suggest that the 35-kDa polypeptide antigen can be a diagnostic marker in active amoebiasis.

Virulence of nonpathogenic zymodemes of Entamoeba histolytica isolates from asymptomatic subjects in Calcuta, India

The zymodene and virulence of 31 Entamoeba histolytica isolates obtained from asymptomatic human subjects in Calcuta, India are described. Virulence was measured by the extent of lesion diameter (mm) induced by each isolated in the liver of golden hamsters and resistance of isolates to non-immmune hamster sera in vitro. Two nonpathogenic zymodemes, III (N=17) and IV (N=14), were detected among 31 isolates by isoenzyme electrophoresis. Most of the zymodeme III isolates were moderately to highly virulent while a quarter of the zymodeme IV were invasive although with low virulence. The virulence of the isolates was found to have a significant positive correlation (r=0.96, P<0.001) with their greater resistance to complement-mediated lysis. The data suggest that the virulence of E. histolytica is probably not related to its zymodeme

Experimental hepatic amoebiasis in inbred mice.

A model of hepatic amoebiasis in two inbred strains of mouse (Swiss and BALB/c, has been developed by introducing Entamoeba histolytica-infected hamster liver tissue in between the adjacent liver lobes of mouse. It is expected that this model might be useful in studying various parameters of host-parasitic interactions and experimental chemotherapy of amoebiasis with relative ease.

Cronkhite-Canada syndrome with hypothyroidism.

An elderly man with non-familial gastrointestinal polyposis, malabsorption and progressive hypoproteinemia is reported. Associated alopecia, cutaneous hyperpigmentation and nail dystrophy with loss of nails were consistent with the diagnosis of Cronkhite-Canada syndrome. Hypothyroidism was present in this patient and the rare association of these two conditions is discussed.

An indirect haemagglutination test to detect serum antibodies to Giardia lamblia.

We used an indirect haemagglutination test with Giardia lamblia trophozoites as the antigen to detect anti-Giardia lamblia antibodies in serum, the soluble tritonated Giardia lamblia antigen being used for detecting anti-giardial antibodies in sera of 60 human subjects. Titers in some of these subjects were 1 : 80-1 : 2560. whereas titers in some subjects were negative button to 1 : 20. The results indicated that Giardia lamblia, an intestinal parasite, induced a systemic antibody response and the indirect haemagglu tination test for anti-Giardia lamblia antibodies is a simple specific and reproducible system which may be useful in epidemiologic and immunologic studies of giardiasis. The specificity of the anti-bodies was demonstrated by the ability of live Giardia lamblia trophozoites, but not Entamoeba histolytica to absorb the antibody activity.

A simple ELISA for antigiardial antibody using the membrane fraction of the parasite as antigen.

Most existing methods for detecting antigiardia lamblia antibody require the use of cultured Giardia lamblia trophozoites as antigen in immunofluorescent and enzyme-linked immunosorbent assays. However, the maintenance of trophozoite culture systems limits the large-scale use of these antibody detection systems. An antigen extracted from Giardia lamblia by the detergent Triton X-100, when used in an ELISA system, produces specific, objective, quantitative and reproducible results. It is likely that such a test system could be packaged in kit form for large-scale diagnostic and epidemiological application in all parts of the world.