Diagnosis of Pathogenic Entamoeba histolytica Infection using a Stool ELISA Based on Monoclonal Antibodies to the Galactose-Specific Adhesin

Abstract

Monoclonal antibodies (MAbs) directed against pathogen-specific epitopes of the galactose adhesin of Entamoeba histolytica were used in an ELISA to detect antigen from pathogenic E. histolytica. Single stool specimens from 74 patients in Bangladesh were used. The ELISA for pathogenic E. histolytica was positive in all 12 stool specimens with pathogenic amebae subsequently cultured, in no stool specimens with nonpathogenic E. histolytica and in 2 of 40 stools with other or no intestinal parasites detected. Specificity and sensitivity of the assay for pathogenic E. histolytica were 97% and 100%, respectively. These preliminary data offer promise for an ELISA using MAbs to the galactose adhesin as a rapid and sensitive means to detect the presence of pathogenic E. histolytica infection in stool specimens.

Historia del protozoo Entamoeba histolytica

“…Ésta es una proteína de la superficie del parásito por la cual se adhiere a las células de la mucosa del colon y otras células blanco 25 . Luego, estudios con técnicas de inmunofluorescencia con anticuerpos monoclonales demostraron la diferencia de los antígenos de superficie entre las dos especies 26,27 . Tannich et al identificaron las diferencias genéticas entre las cepas patógenas y no patógenas 28 .…”

“…Estas pruebas pueden diferenciar E. histolytica de E. dispar al utilizar anticuerpos monoclonales específicos contra Gal/GalNAc lectina, con sensibilidad y especificidad mayores a 90%, además no requieren de personal especializado para su realización y en áreas endémicas permiten diferenciar infección reciente de pasada [31][32][33][34][35] .…”

Evaluation of Two Methods (Nativ-Lugol Preparation and Enzyme-Linked Immunosorbent Assay) for Detection of Entamoeba histolytica in Stool Samples

“…Bu testlerden Enzyme-Linked Immunosorbent Assay (ELISA) dışkı örneğinde patojen E. histolytica ile apatojen E. dispar ve E. moshkovskii ayrımında E. histolytica'da bulunan Gal-veya GalNAc-bağlayan lektin proteinini saptayan monoklonal antikorları kullanmaktadır. Ayrıca kültürle karşılaştırıldığın-da bu testin duyarlılık ve özgüllüğünün sırasıyla %87 ve %90 olarak saptandığı bildirilmektedir (6)(7)(8) …”

Involvement of the actin cytoskeleton and p21rho-family GTPases in the pathogenesis of the human protozoan parasite Entamoeba histolytica

“…Determining the prevalence of E. histolytica in the population is confounded by the existence of the non-pathogenic but morphologically identical Entamoeba dispar and Entamoeba mushkovskii. Distinguishing between them has required relatively sophisticated zymodeme (4) or ribosomal RNA (5) analysis, though methods based on speciesspecific monoclonal antibodies are now available (6,7). Together, the three Entamoeba species are estimated to infect approximately half a billion people, including up to 20% of those living in the tropics and up to 5% of those in temperate regions (1,2).…”