[This corrects the article DOI: 10.1371/journal.pone.0181962.].

BACKGROUND:This study aimed to determine the frequency of Entamoeba histolytica and Entamoeba dispar infection in school children in the community of Tlaltizapan, in order to understand the dynamics of infection within the school and family spheres of this population. Amoebiasis is an unsolved public health problem and an endemic disease in Mexico. The incidence rate varies depending on the state; the most affected states show the highest numbers of new cases of amoebiasis per year. Previously, we reported the molecular frequency of infection with E. histolytica and/or E. dispar in other rural communities of the state of Morelos.METHODS:Children from 3 schools were studied to estimate the frequency of intestinal parasites through microscopic examination of fresh stool samples. The number of studied individuals were 309 school children. The molecular characterization of E. histolytica or E. dispar was carried out by Polymerase Chain Reaction (PCR) using species-specific primers to amplify short tandem repeats (STR) in non-coding sequences associated with the tRNA gene; the amplified fragments were sequenced and analyzed.RESULTS:Eight different genotypes were obtained from E. dispar isolates with the molecular marker NKD3-D5. None of the cases in which the species E. histolytica was detected developed symptoms attributable to an invasive process of disease. Moreover, the parasitized condition appeared to have no significant impact on the development or nutritional status of affected children. Genotype 1, which corresponds to the reference strain E. dispar SAW760, considered a non-pathogenic amoeba, was the most prevalent.CONCLUSIONS:The comparison of the genotypes of Entamoeba species did not show a correlation between children and their relatives. In this community, the species Entamoeba dispar genotype 1 was the most widespread. Based on the indicators of growth, development and nutrition status, the studied community seems to be reasonably adapted to constant exposure to intestinal parasites, since there were no evidences of a serious impact of the parasitized condition on the children's health.

The role of calreticulin (CRT) in host-parasite interactions has recently become an important area of research. Information about the functions of calreticulin and its relevance to the physiology ofEntamoebaparasites is limited. The present work demonstrates that CRT of both pathogenicE. histolyticaand nonpathogenicE. disparspecies specifically interacted with human C1q inhibiting the activation of the classical complement pathway. Using recombinantEhCRT protein, we demonstrate that CRT interaction site and human C1q is located at the N-terminal region ofEhCRT. The immunofluorescence and confocal microscopy experiments show that CRT and human C1q colocalize in the cytoplasmic vesicles and near to the surface membrane of previously permeabilized trophozoites or are incubated with normal human serum which is known to destroy trophozoites. In the presence of peripheral mononuclear blood cells, the distribution ofEhCRT and C1q is clearly over the surface membrane of trophozoites. Nevertheless, the level of expression of CRTin situin lesions of amoebic liver abscess (ALA) in the hamster model is different in bothEntamoebaspecies; this molecule is expressed in higher levels inE. histolyticathan inE. dispar. This result suggests thatEhCRT may modulate some functions during the early moments of the host-parasite relationship.

Cutaneous amebiasis is the least common clinical form of human amebiasis in Mexico, sexual amebiasis was only occasionally observed before the late 1980s. However, in the last few decades, most of the documented cases of cutaneous amebiasis from around the world are sexually transmitted. We present two cases of sexually transmitted genital amebiasis. The molecular characterization of the Entamoeba species in the affected tissues underlines the importance of an etiological diagnosis using specific and sensitive techniques that avoid the rapid destruction of tissues and the irreversible sequelae to the anatomy and function of the affected organs. In addition, for those interested in the study of the human-amoebic disease relationship and its epidemiology, the detection of a new, mixed infection in an invasive case of amebiasis reveals new perspectives in the study of the extraordinarily complex host-parasite relationship in amebiasis.

Event Abstract Back to Event Effect of Entamoeba histolytica calreticulin in the immune response of patients with acute amoebic liver abscess Miriam Nieves1, Rivas Enrique1, Moran Patricia1, Valadez Alicia1, Garcia Maria Del Carmen1, Rojas Liliana1, Oswaldo Partida-Rodriguez1, Hernandez Eric1, Cerritos Rene1 and Ximenez Cecilia1* 1 NATIONAL AUTONOMOUS UNIVERSITY OF MEXICO, DEPARMENT OF EXPERIMENTAL, FACULTY OF MEDICINE, Mexico Entamoeba histolytica is a human intestinal parasite that causes amoebiasis, which in Mexico is considerate as an endemic disease. Some molecules are involved in pathogenicity and virulence of E. histolytica. It was previously reported that E. histolytica calreticulin (EhCRT) is a highly immunogenic protein in patients with amoebiasis. The aims of this work were to characterize the isotype of antibody response in serum samples of patients during the acute phase of amoebic liver abscess (ALA), to measure the ability of EhCRT to bind human C1q protein and to define the stimulation properties of EhCRT upon peripheral mononuclear blood cells (PMBC). We compared individuals with ALA and healthy subjects, which were characterized by coproparasitoscopic and ELISA assays and took a peripheral blood sample to obtain serum and mononuclear cells. PMBC were isolated and cultured in an in vitro system and stimulated with recombinant rEhCRT. The stimulation index was calculated. Results show that the major isotypes of serum antibodies against EhCRT were IgM and IgG class. Levels of IgA in serum were low and levels of IgE isotype of antibodies were extremely low. Besides, rEhCRT-C1q caused the inhibition of classical complement pathway in vitro. PMBC of patients with ALA display a comparatively higher stimulation index to control PMBC. These preliminary results suggest that EhCRT can be a useful antigen and have a modulating role to the adaptive immune response in invasive amoebiasis. Acknowledgements Work performed with support PAPIIT/UNAM: IN226511 and CONACYT 210CO1-140990. Keywords: Entamoeba histolytica, Carleticulin, Amoebic liver abscess, peripheral mononuclear blood cells, human C1q protein Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Host-pathogen interactions Citation: Nieves M, Enrique R, Patricia M, Alicia V, Maria Del Carmen G, Liliana R, Partida-Rodriguez O, Eric H, Rene C and Cecilia X (2013). Effect of Entamoeba histolytica calreticulin in the immune response of patients with acute amoebic liver abscess. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00763 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Jun 2013; Published Online: 22 Aug 2013. * Correspondence: Prof. Ximenez Cecilia, NATIONAL AUTONOMOUS UNIVERSITY OF MEXICO, DEPARMENT OF EXPERIMENTAL, FACULTY OF MEDICINE, MEXICO CITY, Mexico, cximenez@servidor.unam.mx Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Miriam Nieves Rivas Enrique Moran Patricia Valadez Alicia Garcia Maria Del Carmen Rojas Liliana Oswaldo Partida-Rodriguez Hernandez Eric Cerritos Rene Ximenez Cecilia Google Miriam Nieves Rivas Enrique Moran Patricia Valadez Alicia Garcia Maria Del Carmen Rojas Liliana Oswaldo Partida-Rodriguez Hernandez Eric Cerritos Rene Ximenez Cecilia Google Scholar Miriam Nieves Rivas Enrique Moran Patricia Valadez Alicia Garcia Maria Del Carmen Rojas Liliana Oswaldo Partida-Rodriguez Hernandez Eric Cerritos Rene Ximenez Cecilia PubMed Miriam Nieves Rivas Enrique Moran Patricia Valadez Alicia Garcia Maria Del Carmen Rojas Liliana Oswaldo Partida-Rodriguez Hernandez Eric Cerritos Rene Ximenez Cecilia Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.