ABSTRACT
Entamoeba histolytica calreticulin (EhCRT) is remarkably immunogenic in humans (90-100% of invasive amoebiasis patients). Nevertheless, the study of calreticulin in this protozoan is still in its early stages. The exact location, biological functions, and its role in pathogenesis are yet to be fully understood. The aim of the present work is to determine the location of EhCRT in virulent trophozoites in vivo and the expression of the Ehcrt gene during the development of experimentally induced amoebic liver abscesses (ALA) in hamsters. Antibodies against recombinant EhCRT were used for the immunolocalization of EhCRT in trophozoites through confocal microscopy; immunohistochemical assays were also performed on tissue sections of ALAs at different times after intrahepatic inoculation. The expression of the Ehcrt gene during the development of ALA was estimated through both in situ RT-PCR and real-time RT-PCR. Confocal assays of virulent trophozoites showed a distribution of EhCRT in the cytoplasmic vesicles of different sizes. Apparently, EhCRT is not exported into the hepatic tissue. Real-time RT-PCR demonstrated an over-expression of the Ehcrt gene at 30 min after trophozoite inoculation, reaching a peak at 1-2 h; thereafter, the expression fell sharply to its original levels. These results demonstrate for the first time in an in vivo model of ALA, the expression of Ehcrt gene in E. histolytica trophozoites and add evidence that support CRT as a resident protein of the ER in E. histolytica species. The in vivo experiments suggest that CRT may play an important role during the early stages of the host-parasite relationship, when the parasite is adapting to a new environment, although the protein seems to be constitutively synthesized. Moreover, trophozoites apparently do not export EhCRT into the hepatic tissue in ALA.
Subject(s)
Calreticulin/metabolism , Entamoeba histolytica/metabolism , Liver Abscess, Amebic/metabolism , Protozoan Proteins/metabolism , Trophozoites/metabolism , Animals , Blotting, Western , Calreticulin/genetics , Calreticulin/immunology , Cricetinae , Disease Models, Animal , Endoplasmic Reticulum/metabolism , Entamoeba histolytica/genetics , Entamoeba histolytica/immunology , Gene Amplification , Gene Expression , Host-Parasite Interactions , Liver/metabolism , Liver/parasitology , Liver/pathology , Liver Abscess, Amebic/parasitology , Liver Abscess, Amebic/pathology , Mesocricetus , Mice , Mice, Inbred BALB C , Microscopy, Confocal , Recombinant ProteinsABSTRACT
The frequency of Entamoeba histolytica and Entamoeba dispar infection was analyzed in a rural community in the state of Morelos, Mexico, using polymerase chain reaction (PCR). Sociodemographic variables as risk factors for the infection were assessed. Results highlighted the number of individuals with intestinal parasites (43.1%) in the community, indicating extensive fecalism. A high frequency of E. histolytica asymptomatic infection, higher than E. dispar infection (13.8% versus 9.6%), was detected by PCR. Anti-amebic antibody levels (IgG) in serum and saliva (IgA) samples were not associated with E. histolytica intestinal infection. These findings suggest a predominant distribution of E. histolytica strains of low invasive potential in this community.
Subject(s)
Dysentery, Amebic/epidemiology , Entamoeba histolytica , Liver Abscess, Amebic/epidemiology , Animals , Antibodies, Protozoan/blood , Base Sequence , DNA Primers , Entamoeba histolytica/genetics , Entamoeba histolytica/isolation & purification , Family , Feces/parasitology , Humans , Mexico/epidemiology , Polymerase Chain Reaction , Risk Factors , Rural Population , Water SupplyABSTRACT
The frequency of Entamoeba histolytica and Entamoeba dispar infection was analyzed in a rural community in the state of Morelos, Mexico, through PCR technique by using specie specific primer. The E. histolytica specie was detected in 33 of 290 analyzed stool samples (11.4%), E. dispar specie was observed in 21 samples (7.2%) and both species of Entamoeba were detected in seven samples (2.4%). So a higher E. histolytica than E. dispar frequency infection was detected (13.8 versus 9.6%). Even though in our design we did not considered the follow-up of included individuals, the absence of invasive amebiasis cases in the studied population during our stay in town was unexpected.
