Enzyme-linked immunosorbent assay based on monoclonal and polyclonal antibodies for the detection of Entamoeba histolytica antigens in faecal specimens

Abstract

A murine monoclonal antibody (MAb) (Eh208C2-2) raised against crude lysate of the pathogenic HM- 1:IMSS strain of Entamoeba histolytica was used in an enzyme-linked immunosorbent assay for the detection of E. histolytica antigens in faecal specimens. The detection limit of the assay was 110 and 280 amoebae/ml of the HM-1:IMSS and HK-9 strains in phosphate-buffered saline, respectively. The assay was applied to single stool samples from 3 groups of individuals comprising 40 patients whose stools were positive for E. histolytica trophozoites and/or cysts (group I), 48 patients whose stools were negative for E. histolytica but positive for other parasites (group II), and 36 parasitologically-negative healthy controls (group III). Positiv- ity rates of 77.5%, 2.1% and 2.7% were found in samples from groups I, II and III respectively. Specificity, positive and negative predictive values, and efficiency of the assay were 97.6%, 93.9%, 90.1% and 91.1% respectively. When group I samples were further divided into a trophozoite-positive subgroup IA (13 samples) and a cyst-positive subgroup IB (27 samples), the positive rates were 100% and 66.7%, respectively (P<0.025). © Oxford University Press.