Protection against murine intestinal amoebiasis induced by oral immunization with the 29 kDa antigen of Entamoeba histolytica and cholera toxin.

Entamoeba histolytica antigens recognized by salivary IgA from infected patients include the 29 kDa antigen (Eh29), an alkyl hydroperoxide reductase. Here, we investigate the potential of recombinant Eh29 and an Eh29-cholera toxin subunit B (CTxB) fusion protein to confer protection against intestinal amoebiasis after oral immunization. The purified Eh29-CTxB fusion retained the critical ability to bind ganglioside GM(1), as determined by ELISA. Oral immunization of C3H/HeJ mice with Eh29 administered in combination with a subclinical dose of whole cholera toxin, but not as an Eh29-CTxB fusion, induced elevated levels of intestinal IgA and serum IgG anti-Eh29 antibodies that inhibited trophozoites adherence to MDCK cell monolayers. The 80% of immunized mice seen to develop IgA and IgG immune responses showed no evidence of infection in tissue sections harvested following intracecal challenge with virulent E. histolytica trophozoites. These results suggest that Eh29 is capable of inducing protective anti-amoebic immune responses in mice following oral immunization and could be used in the development of oral vaccines against amoebiasis.

Varón de 3 años de edad con rasgos dismórficos y craneosinostosis: síndrome de Saethre-Chotzen / A three year old boy with dysmorphic and craniosynostosis traits: Saethre-Chotzen syndrome

Se comunica el caso de un niño con el síndrome de Saethre-Chotzen (acrocefalosindactilia de tipo III), una de las craneosinostosis más frecuentes, y se describe la mutación causal en el gen TWIST (AU)

It is informed of a child with the Saethre-Chotzen syndrome (acrocephalosyndactylia of type III), one of the most frequent craniosynostosis, and it is described as a causal mutation in the TWIST gene (AU)

Reducción de la frecuencia de la cetoacidosis diabética en niños de 0-14 años / Reduction in diabetic ketoacidosis frequency in 0-14 year old children

No disponible

No disponible

Lesiones cutáneas hipopigmentadas y facies particular / Hypopigmented skin lesions and coarse facies

No disponible

Colecistitis aguda litiásica como presentación excepcional de enfermedad celíaca / Acute lithiasic cholecystitis as an exceptional presentation of celiac disease

No disponible

Intestinal amoebiasis: delayed-type hypersensitivity response in mice.

Delayed-type hypersensitive (DTH) response was evaluated in C3H/HeJ mice intestinally infected with Entamoeba histolytica. Infected and non-infected control mice were challenged with amoebic antigen on day 5, 10, 15, 20, 25, 30, 40, 50, and 60 post-infection. Maximum footpad swelling was observed after 24 hours of the challenge. The E. histolytica-infected mice exhibited a DTH response on day 5, 15, 20, 25, 40 and 60 post-infection. However, on day 10, 30, and 50, such response was similar to that of the non-infected control mice. The mice developed an evident DTH response late in the course of infection (25 days post-infection). The infected mice did not show any alteration to their DTH response against heterologous unrelated antigen (sheep red blood cells), suggesting that cellular anergy was antigen-specific.

Cloning and characterization of Entamoeba histolytica antigens recognized by human secretory IgA antibodies.

To identify the Entamoeba histolytica antigens capable of inducing secretory IgA (sIgA) responses in humans, a cDNA library from the strain HM1:IMSS was immuno-screened with saliva from patients with intestinal amebiasis or amebic liver abscess. Clones isolated with sIgA antibodies from patients with intestinal amebiasis corresponded to the known serine-rich protein isoform, a 29 kDa cysteine-rich protein and 1-alpha elongation factor. Clones corresponding to enolase, cyclophilin, ribosomal protein L23a, and an Hsp70 family protein were isolated with sIgA from a patient with amebic liver abscess. A glutamic acid-rich peptide (EhGARP) positive with sIgA from a patient with amebic liver abscess was also isolated; for EhGARP, no homologs were found in the protein databases. The antigens isolated are potentially useful in the development of an oral vaccine or new diagnostic tools for amebiasis.

Experimental amebiasis: immunohistochemical study of immune cell populations.

Distribution of immune cell populations was studied in a C3H/HeJ mouse model of intestinal amebiasis from 5 to 60 days post-inoculation with Entamoeba histolytica, using immunoperoxidase techniques. At various time intervals, the ceca from mice were fixed in 10% formalin, dehydrated, embedded and sectioned at 5 microm. Sections were incubated with conjugated peroxidase-labelled antibodies to mouse IgA, IgM, and IgG. Color was developed with 3, 3'-diaminobenzidine tetrahydrochloride (DAB)/H2O2 solution. CD3, CD4, and CD8 cells, as well as neutrophils were detected by reacting with biotin-conjugated anti-mouse CD3, CD4, CD8, and CD11 monoclonal antibodies, followed by their incubation with avidin-peroxidase and color development with DAB/H2O2 solution. Erythrocin B and toluidine blue were used to stain eosinophils and Mast cells, respectively. It was observed that the IgA+ plasma cell was the dominating immune cell present in the mucosa, although eosinophils, neutrophils, CD3+, CD4+, CD8+, IgM+, IgG+ cells and Mast cells were also seen. Results of this study suggest that infiltration of immune cells at the mucosal surface during intestinal amebiasis might be important in the defense against this parasite.

Effect of zinc on Entamoeba histolytica pathogenicity.

The present study analyzes the effects of zinc on Entamoeba histolytica activity and on its pathogenicity. Metal activity was evaluated in vitro with regard to the parasite's viability, replication, and adhesion to epithelial cells and in vivo with regard to its pathogenicity. The results obtained in vitro show that zinc at 1.0 mM concentration does not affect amebic viability; however, it does decrease amebic replication and adhesion (P < 0.001). In vivo studies performed on a model of experimental liver abscess in the hamster indicate that the intraperitoneal administration of a single dose of zinc at 48 h after the intrahepatic inoculation of amebic trophozoites significantly inhibits (P < 0.001) abscess development. The results indicate that zinc alters the functionality of the ameba in vitro as reflected by a decrease in replication and adhesion and in vivo as manifested by inhibition of amebic pathogenicity.

Experimental amebiasis: molecular weight analysis of Entamoeba histolytica antigens recognized by IgG antibodies.

The reactivity of sera from experimentally infected animal was studied from 5-60 days postinoculation to determine which of the E. histolytica antigens are recognized frequently to infection. Crude extract of E. histolytica trophozoites was used and sera were examined by immunoelectrotransference assay. It was observed that sera recognized polypeptide with 70 kDa molecular mass after 15 days postinoculation onward and later 14 to 24 polypeptide with molecular weight of 110-22 kDa were recognized. All the amebic antigens (polypeptides) could be recognized by sera till 60 days postinoculated animals. Significance of expression of different amebic polypeptides in terms of pathogenesis needs further investigations.

Secretory immune response in patients with intestinal amoebiasis.

The secretory immune response in saliva from intestinal amoebiasis patients against antigens obtained from Entamoeba histolytica membranes was studied. Western blot analysis indicated that patient saliva contains secretory IgA antibodies against antigens with molecular masses ranging from 170 to 24 kDa, some of which were also recognized by saliva from healthy subjects. However, antigens of 170, 125, 46 and 37 kDa are recognized more frequently (> 90%) by the secretory IgA from patients with intestinal amoebiasis than by that from healthy subjects (< 10%).

Intestinal amoebiasis: antibody-secreting cells and humoral antibodies.

Splenic plasma cell response and systemic antibody response to intestinal amoebiasis were studied in C3H/HeJ mice from 5 to 60 days post-inoculation with Entamoeba histolytica. At various time intervals specific antibody-secreting cells (ASC) in the spleen were measured in infected mice and non-infected control mice by enzyme-linked immunospot (ELISPOT) assay. Serum antibodies were measured by enzyme-linked immunosorbent assay (ELISA). The infected animals showed high IgA ASC from 30 to 50 days post-inoculation as compared to IgM and IgG ASC. However, class-specific serum antibody showed high IgG titre from 30 to 60 days post-inoculation as compared to IgM and IgA serum titres. Our results suggest that E. histolytica trophozoites can induce a plasma cell response in the spleen that is different from anti-amoebic antibody response in serum.

Rapid screening test for tuberculosis using a 38-kDa antigen from Mycobacterium tuberculosis.

A screening test for the diagnosis of tuberculosis by immunodot (IDt) is described, using an antigen of Mycobacterium tuberculosis, namely, a 38-kDa glycoprotein which has shown great specificity in previous serologic analyses. The test was used to examine 28 sera from patients with lung tuberculosis. Of these, 85% were positive by micro-ELISA and by the IDt test herein described. Control sera from healthy subjects (n = 20) gave negative results for ELISA and for IDt, which indicates that the screening test is highly specific. The test is easy to handle and requires no equipment and is therefore particularly useful for field studies.

Secretory immune response to membrane antigens during Giardia lamblia infection in humans.

The secretory immune response in humans infected with Giardia lamblia was studied by using saliva samples and a membrane-rich protein fraction. The membrane fraction, studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showed 24 antigen bands, ranging from 170 to 14 kDa. Saliva samples from giardiasis patients showed a heterogeneous response against the membrane fraction when they were assayed by immunoblotting. Among the antigens recognized by patient saliva samples, those of 170, 105, 92, 66, 32, 29, and 14 kDa stood out. These antigens were not recognized by saliva samples from healthy individuals. They may be of importance in future studies of protection from or diagnosis of G. lamblia infections.

Antigen association of total HEp-2 cell extract in the screening of autoimmune diseases by western blot.

Sera from patients with autoimmune diseases and healthy individuals were comparatively analyzed by Western blot, using total extract from HEp-2 cells as antigen. Bands between 14 and 20 kDa were present in 99% of patients with autoimmune diseases and symptomatic seronegative patients, in contrast to only 4% of healthy controls. No bands were detected in the remaining 96% of healthy controls. We propose these antigens as pathologically important for the diagnostic screening of patients with suspected autoimmune disease.

Carbohydrate epitopes of Entamoeba histolytica cell surface glycoproteins are major targets of the human humoral response.

The antigens of Entamoeba histolytica recognized by antibodies in 11 individual sera from patients treated for amebic liver abscess were determined both by immunoprecipitation of metabolically-radiolabeled whole trophozoite proteins and by immunoblotting.Collectively, twenty-s even antigens ranging from 167 to 21 kDa were detected in immunoblots of whole trophozoite extracts; eight of these were recognized by all tested patient sera. Immunoprecipitation studies also revealed a complex amebic antigenic profile. Of a total of twenty immunoprecipitated polypeptides (from 200 to 24 kDa), seventeen were uniquely recognized by the patient sera. Eight of these seventeen antigens were immunoprecipitated by most immune sera. The cellular localization of trophozoite antigens was determined by analyzing plasma membrane and soluble cytosol fractions. Plasma membranes contained virtually as many antigenic moieties as the total trophozoite extract; in contrast, the soluble fraction was antigenically less complex. Mild periodate oxidation of plasma membrane antigens indicated that surface glycoproteins are highly immunogenic for the human host and that antibodies to their carbohydrate epitopes are a major component of the total response of most patients.