Analysis Of Excretory-Secretory Antigen Of Entamoeba Histolytica For Detection Of Amoebic Liver Abscess
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Date
2011-11
Authors
Wong, Weng Kin
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Amoebiasis is an enteric protozoan disease caused by Entamoeba histolytica. It affects 50 million people worldwide and causes up to 100,000 fatal cases annually. Amoebic liver abscess (ALA) is the most common clinical manifestation of extraintestinal amoebiasis. It can lead to fatal outcome if early diagnosis and treatment are not obtained. To date, diagnosis of ALA is dependent on clinical history, radiological imaging, and laboratory diagnosis. Serodiagnosis is widely used because it is non-invasive and easy to perform. However, the commonly used immuno-haemagglutination assay (IHA) and TechLab E. histolytica II ELISA showed low sensitivities in endemic areas due to the high anti-amoebic antibody background in the population and prior treatment of patients. Thus, the aims of this study were to analyse the antigenic proteins of excretory-secretory antigen (ESA) collected from E. histolytica, and to identify potential biomarker(s) which could improve the serodiagnosis of ALA.
A protein-free defined medium supplemented with 0.1 % L-cysteine and 0.02 % ascorbic acid which could sustain the ≥ 95 % viability of the anaerobic trophozoite for at least 8 hours i.e. DMEM-C&A or RMPI-C&A was optimized and the latter used for ESA preparation. The incubation period of trophozoites in the medium was reduced to 6 hours, in order to compensate the time used for harvesting the mass cultured trophozoites. The maximum trophozoites density in the medium was 0.8 x 106 cells per mL. ESA was then collected, concentrated and buffer-exchanged prior to use. Western blot analysis of ESA probed with human serum samples with ALA (n = 38) revealed two antigenic proteins with sensitivities above 80 %, i.e. 152 kDa and 110 kDa.
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Keywords
Analysis of excretory-secretory antigen , of Entamoeba histolytica