Entamoeba histolytica: Membrane and Non-Membrane Protein Structure, Function, Immune Response Interaction, and Vaccine Development.

Entamoeba histolytica is a protozoan parasite that is the causative agent of amoebiasis. This parasite has caused widespread infection in India, Africa, Mexico, and Central and South America, and results in 100,000 deaths yearly. An immune response is a body's mechanism for eradicating and fighting against substances it sees as harmful or foreign. E. histolytica biological membranes are considered foreign and immunogenic to the human body, thereby initiating the body's immune responses. Understanding immune response and antigen interaction are essential for vaccine development. Thus, this review aims to identify and understand the protein structure, function, and interaction of the biological membrane with the immune response, which could contribute to vaccine development. Furthermore, the current trend of vaccine development studies to combat amoebiasis is also reviewed.

Prevalence and Risk Factors of Bovine Fascioliasis in Kelantan, Malaysia: A Cross-Sectional Study.

Bovine fascioliasis is an important zoonotic parasitic disease that causes significant economic losses to the livestock industry. The aim of this study was to determine the prevalence and risk factors of bovine fascioliasis in Kelantan. In this cross-sectional study, a total of 308 stool and blood samples of farmed cattle were collected from December 2017 to June 2018. The stool samples were examined microscopically for the presence of Fasciola spp. eggs following a formalin-ether sedimentation process. The blood samples were subjected to a commercial ELISA kit (Bio-X-Diagnostic, Rochefort, Belgium) for the detection of anti-Fasciola IgG antibody. The association between coprological findings and risk factors was determined using Pearson's chi-square (χ2). The coproprevalence and seroprevalence of bovine fascioliasis was 14.6% and 37.3%, respectively. There were significant (P < 0.05) associations between the risk of infections and the sex, type of feedings, anthelmintic treatment and farm hygiene. Female cattle (OR: 3.104; 95% CI: 1.265, 7.615), feeding by grazing (OR: 4.458; 95% CI: 1.823, 10.90), untreated cattle (OR: 3.833; 95% CI: 1.620, 9.071), non-schedule anthelminthic treatment (OR: 3.927; 95% CI: 1.685, 9.152) and farm that have never been cleaned (OR: 2.829; 95% CI: 1.428, 5.608) showed higher odds of Fasciola spp. infection. These findings suggested bovine fascioliasis is a serious veterinary disease in Kelantan. Thus, appropriate control, prevention and monitoring strategies of this parasitic infection are urgently needed to reduce the burden of the disease.

Fascioliasis pada lembu adalah penyakit parasit zoonotik penting yang menyebabkan kerugian ekonomi yang signifikan pada industri ternakan. Tujuan kajian ini adalah untuk menentukan prevalens dan faktor risiko fascioliasis pada lembu ternak di Kelantan. Dalam kajian keratan rentas ini, sejumlah 308 sampel tinja dan sampel darah daripada lembu ternak telah diambil dari Disember 2017 hingga Jun 2018. Sampel tinja telah diperiksa secara mikroskopik bagi mengesan kehadiran telur Fasciola spp. melalui proses sedimentasi formalin-eter. Sampel darah telah disaring menggunakan kit ELISA komersial (Bio-X-diagnostics) untuk pengesanan antibodi anti-Fasciola IgG. Hubungan antara penemuan koprologi dan faktor risiko telah ditentukan dengan menggunakan ujian Chi-ganda dua (χ2). Koproprevalens dan seroprevalens fascioliasis pada lembu masingmasing adalah 14.6% dan 37.3%. Terdapat perbezaan signifikan (P < 0.05) antara risiko jangkitan dan jantina, kaedah pemakanan, penggunaan ubat cacing dan kebersihan ladang. Lembu betina (OR: 3.104; 95% CI: 1.265, 7.615), kaedah pemakanan melalui teknik ragut (OR: 4.458; 95% CI: 1.823, 10.90), lembu yang tidak dirawat (OR: 3.833; 95% CI: 1.620, 9.071), rawatan secara tidak berkala (OR: 3.927; 95% CI: 1.685, 9.152) dan ladang yang tidak pernah dibersih (OR: 2.829; 95% CI: 1.428, 5.608) merupakan antara risiko lebih tinggi untuk dijangkiti Fasciola spp.. Penemuan ini mencadangkan bahawa fascioliasis pada lembu adalah penyakit veterinar yang serius di Kelantan. Oleh itu, strategi kawalan, pencegahan dan pengawasan yang sesuai bagi jangkitan parasit ini amat diperlukan untuk mengurangkan beban penyakit ini.

Entamoeba histolytica acetyl-CoA synthetase: biomarker of acute amoebic liver abscess.

OBJECTIVE: To characterize the Entamoeba histolytica (E. histolytica) antigen(s) recognized by moribound amoebic liver abscess hamsters. METHODS: Crude soluble antigen of E. histolytica was probed with sera of moribund hamsters in 1D- and 2D-Western blot analyses. The antigenic protein was then sent for tandem mass spectrometry analysis. The corresponding gene was cloned and expressed in Escherichia coli BL21-AI to produce the recombinant E. histolytica ADP-forming acetyl-CoA synthetase (EhACS) protein. A customised ELISA was developed to evaluate the sensitivity and specificity of the recombinant protein. RESULTS: A ∼75 kDa protein band with a pI value of 5.91-6.5 was found to be antigenic; and not detected by sera of hamsters in the control group. Tandem mass spectrometry analysis revealed the protein to be the 77 kDa E. histolytica ADP-forming acetyl-CoA synthetase (EhACS). The customised ELISA results revealed 100% sensitivity and 100% specificity when tested against infected (n=31) and control group hamsters (n=5) serum samples, respectively. CONCLUSIONS: This finding suggested the significant role of EhACS as a biomarker for moribund hamsters with acute amoebic liver abscess (ALA) infection. It is deemed pertinent that future studies explore the potential roles of EhACS in better understanding the pathogenesis of ALA; and in the development of vaccine and diagnostic tests to control ALA in human populations.

Evaluation of Entamoeba histolytica recombinant phosphoglucomutase protein for serodiagnosis of amoebic liver abscess.

BACKGROUND: Amoebic liver abscess (ALA) is the most frequent clinical presentation of extra-intestinal amoebiasis. The diagnosis of ALA is typically based on the developing clinical symptoms, characteristic changes on radiological imaging and serology. Numerous serological tests have been introduced for the diagnosis of ALA, either detecting circulating amoebic antigens or antibodies. However those tests show some pitfalls in their efficacy and/or the preparation of the tests are costly and tedious. The commercial IHA kit that used crude antigen was reported to be useful in diagnosis of ALA, however high antibody background in endemic areas may cause problems in its interpretation. Thus, discovery of well-defined antigen(s) is urgently needed to improve the weaknesses of current serodiagnostic tests. METHODS: Crude antigen of E. histolytica was analysed by 2-DE and Western blot to identify a protein of diagnostic potential for ALA. The corresponding gene of the antigenic protein was then cloned, expressed and the purified recombinant protein was subsequently evaluated for serodiagnosis of ALA in an indirect ELISA format. RESULTS: Analysis of crude antigen showed that phosphoglucomutase (PGM) has the diagnostic potential. Recombinant PGM (rPGM) showed 79.17% (19/24) sensitivity and 86.67% (195/225) specificity in diagnosis of ALA based on the COV of mean +1SD. There was no significant difference between rPGM-ELISA and IHA diagnostic kit in the diagnosis of ALA in terms of sensitivity and specificity at p-value < 0.05. CONCLUSION: In conclusion, rPGM-ELISA is found to be useful for serodiagnosis of ALA. Future studies will determine whether rPGM-ELISA also detects antibodies produced in amoebic dysentery and asymptomatic cases.

Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess: comparison of three staining methods.

OBJECTIVE: To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster. METHODS: Amoebic liver abscess was experimentally induced in a hamster by injecting 1 × 10(6) of axenically cultured virulent E. histolytica trophozoites (HM1-IMSS strain) into the portal vein. After a week post-inoculation, the hamster was sacrificed and the liver tissue sections were stained with H&E, PAS and IHC stains to detect the amoebic trophozoite. RESULTS: The three stains revealed tissue necrosis and amoebic trophozoites, but with varying clarity. H&E and PAS stained the trophozoites pink and magenta, respectively, however it was difficult to differentiate the stained trophozoites from the macrophages because of their similarity in size and morphology. On the other hand, IHC stain revealed distinct brown appearance of the trophozoites in the infected liver tissues. CONCLUSIONS: It can be concluded that out of the three stains, IHC is the best for identification of E. histolytica trophozoites in tissue sections.