A reliable and specific enzyme-linked immunosorbent assay for the capture of IgM from human chagasic sera using fixed epimastigotes of Trypanosoma cruzi

Abstract

A rapid, sensitive, specific, and reliable enzyme-linked immunosorbent assay (ELISA) is proposed for determination of the levels of anti-Trypanosoma cruzi IgM in acute chagasic sera (ACD). The efficiency of this ELISA as a diagnostic method was compared with that of parasite DNA detection by polymerase chain reaction (PCR) and that of indirect immunofluorescence (iIF) anti-T. cruzi IgM detection. We tested whether this ELISA using fixed epimastigotes (epi) could detect anti-T. cruzi IgM in serum samples from two groups of children with acute Chagas' disease from a hyperendemic area in Bolivia. In a comparison of the ELISA method with other techniques, 95% and 71% of the results correlated with PCR and iIF findings, respectively. At the serum dilution applied (1:250), rheumatoid factor (RF) did not influence the results, and samples from patients carrying leishmaniasis or mixed Leishmania and T. cruzi infection could also be excluded from ACD. Highly specific and reliable results were obtained, a great number of the sera could be tested in only one assay, and a quantitative index of reactivity (IR) could be calculated without serial titration. Using test samples in triplicate, the method provides a useful tool for the detection of early acute-phase T. cruzi infection in humans.

Combined Use of Enzyme-Linked Immunosorbent Assay and Flow Cytometry To Detect Antibodies toTrypanosoma cruziin Domestic Canines in Texas

“…Canine serum samples were tested for antibodies to T. cruzi by using a modification of protocols previously described (1,8,29). Fixed whole epimastigotes were washed and resuspended at a concentration of 500,000 epimastigotes per ml in 0.05 M carbonate buffer, pH 9.6.…”

HumanTrypanosoma cruziInfection and Seropositivity in Dogs, Mexico

“…cruzi by enzyme-linked immunosorbent assay (ELISA) as previously described ( 20 , 21 ). All samples and controls were assayed in triplicate in at least 2 independent experiments.…”

Chagas Disease Diagnostic Applications

“…In this context, identification of novel antigens recognized by fetal IgM or IgA appeared as an appealing approach. However, and despite initial promising results (Antas et al, 2000; Betonico et al, 1999; Corral, Altcheh and Freilij, 1998; Lorca et al, 1995), these efforts have been discontinued due to the high number of false-negatives (Blanco et al, 2000; Freilij and Altcheh, 1995; Gomes, Lorena and Luquetti, 2009). It should be noted though, that a serious, high-content and unbiased screening for congenital IgM specificities have not been yet undertaken.…”