Effect of histamine and glucose on encystation of Entamoeba histolytica in vitro

Isolates of Entamoeba histolytica grown and maintained in modified Boeck and Drbohlav's medium were used to examine the effect of histamine and glucose on encystation process in vitro. This revealed that 60-74% of the active and motile trophozoites of E. histolytica encysted within 72 hours in the presence of histamine and glucose, in contrast to 10-20% encystment in controls (with out histamine and glucose); a highly significant difference (P < 0.001). These observations also suggest the possibility of active role of histamine and glucose in encystation of E.histolytica in vivo.

Leucocyte migration inhibition index responses of patients of amoebic liver abscess to various antigens of Entamoeba histolytica

The whole amoebic lysate (WAL), Sephadex G-200 eluted fraction-I. (F-I), detergent dissected membrane proteins (DDMP), amoebic membrane glycoprotein (AMG) and amoebal RNA were extracted from E. histolytica. Amoebal RNA recognized 98.21% where as F-I, AMG, DDMP and WAL recognised 92.85, 91.07, 89.28 and 75% of total 56 clinically proven and amoebic serology positive amoebic liver abscess cases respectively. Intensity of recognition of individual fraction i.e., leucocyte migration inhibition index of each fraction was found to be highly significant (P < 0.001) when compared to whole amoebic lysate. This indicate the leucocyte migration inhibition index responses of patients of amoebic liver abscess to various antigenic fractions of E. histolytica with variations.

A comparative study of different isolated fractions of Entamoeba histolytica in amoebic liver abscess

Fifty six patients with amoebic liver ubscess were assessed for antibody production and lymphokine release using different antigenic fractions such as sephadex G-200 eluted fraction-I (F-I), shed of bile salt treated amoebae (SBSTA), amoebic membrane glycoprotein (AMG), amoebic RNA and whole amoebic lysate (WAL). Antibody production in response to WAL, F-I, SBSTA, AMG and RNA was assessed by indirect haemagglutination assay. Five and 53 fold increased titres of IHA was observed with F-I and SBSTA respectively compared to WAL. The difference between mean titres of F-I, SBSTA and WAL was found to be highly significant (P < 0.001). Amoebic RNA did not show pronounced antibody titres. Lymphokine release by T lymphocytes in response to F-I, SBSTA, AMG, RNA and WAL was assessed by leukocyte migration inhibition (LMI) test. A highly increased release of LMIF by RNA, AMG, F-I and SBSTA was observed compared to whole amoebic lysate. The difference between the means of the purified fractions and WAL, to release of LMIF was found to be highly significant (P 0.001). These findings suggest that SBSTA, F-I and AMG fractions might have an important role as a potent antigen in inducing humoral and cell mediated immunity in patients with amoebic liver abscess and these findings also confirm the multiple antigenicity of E. histolytica.

Antibody-induced alterations of Na+/K(+)-ATPase activity in rabbit red blood cells during experimental thyroglobulin immunization

Thyroid hormone modulates cell membrane Na+/K(+)-ATPase. A detailed study of erythrocyte membrane Na+/K(+)-ATPase activity was carried out during experimental thyroglobulin immunization. During the process of immunization there was a sharp decline in Na+/K(+)-ATPase activity until the 98th day of immunization, when the thyroglobulin antibody titer was at its peak. This enzyme activity retained a lower level although a fall in antibody titer occurred up to the 147th day.

Detection of antibodies to serum IgA and IgG in peptic ulcer cases by indirect haemagglutination test

Autoantibodies to serum IgA and IgG were detected in 206 peptic ulcer patients (196 duodenal ulcer and 10 gastric ulcer) and 52 healthy age and sex-matched controls by indirect haemagglutination test. A significantly increased mean titre of autoantibodies to serum IgA was observed in the peptic ulcer patients. Forty-eight (24.61%) duodenal ulcer cases had autoantibody titre values above mean +/- 2 SD of controls. Titres of autoantibodies to serum IgG were significantly increased only in the gastric ulcer cases. The results suggest an immunologic abnormality in a sizeable fraction of these cases.

Isoenzyme pattern of clones of Entamoeba histolytica

The isoenzyme pattern of clones of E. histolytica isolated from symptomatic and asymptomatic patients of amoebiasis were determined by starch gel electrophoresis. Ten parent cultures (uncloned), 5 from symptomatic and 5 from asymptomatic patients were isolated and established in Robinsons medium as xenic cultures. A total of 100 clones were isolated from parent cultures but only 65 could be established. Starch gel electrophoresis was carried out on the uncloned and cloned cultures. The analysis showed that the 5 uncloned culture from symptomatic patients had 4 isolates with pathogenic zymodeme and 1 isolate with non-pathogenic zymodeme pattern. The presence of beta band and absence of alpha band for phosphoglucomutase (PGM) and a fast moving Hexokinase (HK) band were taken as markers of pathogenicity. The 5 cloned cultures from asymptomatic patients had three isolates with pathogenic and 2 with non-pathogenic pattern. The cloned isolates from symptomatic patients (35) had 20 pathogenic zymodemes and asymptomatic patients (30) had 15 pathogenic zymodemes. Non-pathogenic zymodeme obtained in the present study were I, IV, V, X and XIII and the pathogenic zymodemes obtained were II and XIV. The data of the study indicated that (i) asymptomatic patients also harbour pathogenic zymodemes; and (ii) zymodeme II also coexsist with zymodeme XIV in the Indian population.

Correlation between membrane glycoprotein and detergent dissected membrane protein in the assessment of LMIF: a report of 51 ALA cases

Assessment of 51 amoebic liver abscess cases for leukocyte migration inhibition factor released using membrane glycoprotein and detergent dissected membrane protein (DDMP) of axenic Entamoeba histolytica (NIH:200). Lymphokines release by T lymphocytes in response to purified amoebic membrane glycoprotein (PAMG) against whole amoebic lysate (WAL), dissect out protein against whole amoebic lysate and membrane glycoprotein against dissected protein was tested by leukocyte migration inhibition test on blood samples from proved amoebic liver abscess cases. A significant increase was noted in the release of lymphokines and 100% positivity was observed with both PAMG and DDMP compared to 78% with whole amoebic lysate. The difference between means leukocyte migration indices of the membrane glycoprotein and whole amoebic lysate, detergent dissected protein and whole amoebic lysate with regards to release LMIF were found to be highly significant (P < 0.001), (P < 0.005) respectively. But insignificant difference and very much similarity was noted between the means of membrane glycoprotein and dissect out protein sensitized T lymphocytes with regards to lymphokine release in vitro. This shows the patients had high degree of leukocyte sensitized to pure amoebic membrane glycoprotein and detergent dissected membrane protein compared to whole amoebic lysate. These findings indicate that detergent dissected protein has similar antigenicity with membrane glycoprotein in elicitation cell mediated immune response in amoebic liver abscess cases.

Detection of sialic acid in trophozoites of Entamoeba histolytica (NIH:200)

In two successive experiments detection of sialic acid was achieved from trophozoites of axenically grown E. histolytica (NIH:200) using silicic acid column chromatography for the separation of sialosylated lipids and asialosylated lipids from total lipids. Sialic acid of the sialosylated lipids was detected through thiobarbituric acid assay followed by acid hydrolysis. These findings indicate that presence of sialic acid is not only a character of the cystic stage but also that of trophozoites of E. histolytica. Detection of sialic acid confirmed the electronegative charge of the surface membrane (glycocalyx) of E. histolytica trophozoites.

Correlation between antiamoebic IgG and autoreactive anti-IgG in amoebic liver abscess cases

IgG isolated and purified from a healthy human serum through Sephadex G-200 and protein A CL 4B sepharose chromatography was used for detection of its own antibodies and correlated with the antiamoebic antibody titres in amoebic liver abscess cases. The mean titres with standard deviation of the self reactive antibodies to serum IgG both ALA cases and healthy controls show a highly significant difference, and antiamoebic antibody titres (IgG) are very much correlated with the autoreactive anti IgG titres in amoebic liver abscess cases. This correlation suggests that as antiamoebic IgG levels reach to its maximum, autoreactive anti IgG are produced to switch off antiamoebic anti IgG production in amoebic liver abscess cases.

Detection and characterization of circulating immune complexes in peptic ulcer

BACKGROUND

Immunological factors have been implicated in the pathogenesis of peptic ulcer following the demonstration of autoantibodies against IgA in patients with this disease. We investigated whether circulating immune complexes were present in this condition, and what type of immunoglobulins were involved.

METHODS

The sera of 37 patients with duodenal ulcer and 8 with gastric ulcer were tested for the presence of circulating immune complexes using the polyethylene glycol (PEG) assay and the results compared with those in 79 controls. The precipitate was dissociated and the levels of IgA, IgG and IgM estimated using the single radial immunodiffusion technique. Simultaneous estimation of these immunoglobulins in the serum was also done. Autoantibodies against IgA in the serum were tested using the ELISA test.

RESULTS

Eleven patients (6 with duodenal ulcer and 5 with gastric ulcer) were found to have circulating immune complexes. The mean protein content of the PEG precipitates was significantly higher in patients than in control subjects (p < 0.001). The mean values of all the immunoglobulin isotypes were higher in patients than in controls. The IgA content in the PEG precipitates of positive cases was higher than that in control subjects (p < 0.05).

CONCLUSION

Patients with peptic ulcer have circulating immune complexes which may interfere with normal immunoregulation.

Role of pure and biologically active amoebal RNA in assessment of lymphokines: a report of 55 ALA cases

Amoebic liver abscess cases (55) were assessed for release of lymphokines (LMIF) using pure and biologically active amoebal RNA of axenic Entamoeba histolytica (NIH: 200) obtained with cesium chloride centrifugation. Lymphokines released by T lymphocytes in response to both amoebal RNA and whole amoebic lysate (WAL) were tested by leukocyte migration inhibition test (LMIT) on blood samples from amoebic liver abscess cases. A significant increase was observed in the release of lymphokine and 100% positivity was observed with amoebal RNA compared to whole amoebic extract with a positivity of only 78%. The difference between means leukocyte migration inhibition of the above two with regards to release of lymphokine was highly significant (P less than 0.001). This shows that patients had high degree of leukocyte sensitization to amoebal RNA of E. histolytica compared to whole amoebic lysate. These findings suggest that the amoebal RNA plays an important role as a potent antigen in the elicitation of cell mediated immune responses in amoebic liver abscess cases.

Enteric non-A, non-B hepatitis: epidemics, animal transmission, and hepatitis E virus detection by the polymerase chain reaction

We studied epidemics of viral hepatitis occurring at three different places in India. One was a combined epidemic due to hepatitis E virus (HEV) and hepatitis A virus (HAV) infections. In this epidemic, HAV affected children below 10 years of age, whereas HEV infected the young adult population. HEV was transmitted to rhesus monkeys (Macaca mulata) and confirmed by the polymerase chain reaction (PCR) on bile from the animals. Fecal material from acutely infected patients in one of the epidemics was also found positive for HEV RNA by PCR. This may help in confirming the nature of future epidemics. The bile and liver from experimental animals can be used as a source of material for further virological and molecular biological studies of HEV.

Autoimmunity in amoebiasis

Amoebic liver abscess (ALA) and symptomatic intestinal amoebiasis cases were assessed by indirect haemagglutination assay for auto-reactive IgG and IgA class of antibodies in response to healthy human serum IgG and IgA. The present results indicated the presence of autoreactive IgG and IgA class of antibodies in ALA and intestinal amoebiasis respectively.

Detection of autoreactive antibodies to serum IgG and IgA in amoebic liver abscess cases

Assessment of autoreactive antibodies in response to healthy human serum IgA and IgG was performed by indirect haemagglutination assay on serum samples from 81 amoebic liver abscess cases for IgA and 70 for IgG. Appropriate controls were taken simultaneously. IgA, IgG were isolated and purified from a healthy human serum through Sephadex G-200 and protein A CL 4B sepharose chromatography. These immunoglobulins were used for the detection of its own antibodies in amoebic liver abscess cases. This revealed that 43.20% and 48.50% of the cases were positive for IgA and IgG respectively, where as only 19.35% and 28.30% of the controls were in positive category (IgA and IgG respectively). The mean titres with standard deviation of the autoreactive antibodies to serum IgA both in ALA cases and controls shows a highly significant difference between tests and controls (P less than 0.001). Similarly the mean titres with standard deviation both in ALA and controls for the serum IgG differed significantly (P less than 0.001). This suggests the presence of autoreactive antibodies against serum IgA and IgG in amoebic liver abscess cases.

Studies on urea cycle enzyme levels in the human fetal liver at different gestational ages

Urea cycle enzymes involved in the detoxification of ammonia were studied in liver tissues of 57 male and 49 female fetuses of different age groups ranging from 13 to 36 wk of gestation. Surgical wedge biopsies of liver from 18 male and 12 female adults were used as controls. Significant enzyme activity was found to be present as early as the 13th wk of gestation. As gestational age advanced, enzyme activity gradually increased, reaching about 90% of the adult activity by the 36th wk of gestation.

Detergent dissection of membrane proteins of Entamoeba histolytica and its effect on lymphokine release in in vitro

Fifty-two amoebic liver abscess cases were assessed for the release of lymphokines (LMIF) using detergent dissected membrane proteins (DDMP) of axenic Entamoeba histolytica (NIH:200) obtained with sodium deoxycholate treatment. Lymphokines release by T lymphocytes in response to both DDMP and whole amoebic lysate (WAL) was tested by leukocyte migration inhibition test on blood samples from amoebic liver abscess cases. A significant increase was noted in the release of LMIF and 100% positivity was observed with DDMP compared to whole amoebic extract with a positivity of 73%. The difference between means of the above two with regards to release of LMIF was found to be highly significant (P less than 0.005). This shows the patients had high degree of leukocyte sensitization to surface antigens of E. histolytica compared to the whole amoebic lysate. These findings suggest that the antigens shed might have important role as a potent antigen in elicitation of CMI response in amoebic liver abscess cases.

Immunogenicity of detergent membrane proteins of Entamoeba histolytica

The lymphokine release and antibody production were assessed in the peripheral blood of 52 and 48 cases of amoebic liver abscess respectively, by employing detergent dissected membrane proteins (DDMP) of axenic Entamoeba histolytica (NIH:200). Lymphokine release by T lymphocytes in response to both DDMP and whole amoebic lysate (WAL) was performed by leukocyte migration inhibition test. A highly increased release of LMIF and 100 per cent positivity was observed with DDMP where as the same for whole amoebic extract, was only 73 per cent. The difference between the means of the above two values with regards to release of LMIF, was found to be highly significant (P less than 0.005). Antibodies production in response to both DDMP and whole amoebic lysate was performed by indirect haemagglutination assay on blood samples from amoebic liver abscess cases. A 53 folds increased titres of IHA and cent percent positivity was observed with DDMP compared to WAL. The difference between mean titres of the above two with regards to detection of antibodies, was found to be highly significant (P less than 0.001). This shows that the patients, had high degree of leukocyte sensitization and production of antibodies which will not be assessed simply with WAL. These findings suggest that the shed material might have important role as a potent antigen in elicitation cell mediated and humoral immune response in amoebic liver abscess cases.