Enzyme-linked immunosorbent assay with purified Trypanosoma cruzi excreted superoxide dismutase

Objectives: Purification and biochemical characterization of a highly immunogenic extracellular superoxide dismutase of Trypanosome cruzi Maracay strain. Design and methods: Fractionation with ammonium sulphate (35-85%) and two continuous chromatography processes (ion exchange and filtration). Results: The molecular mass of the excreted SOD purified was 25 kDa and the isoelectric point 3.9. This enzyme was validated by ELISA with the polyclonal sera obtained from Balb-C mice and with sera from 222 chagasic patients from Brazil, Chile, Colombia, Mexico and Peru plus 20 sera corresponding to leishmaniasis from Peru. All the sera from Brazil stored since 1980 were positive, 93% were positive in chronic patients with 10 years of Chagas treatment from Chile, and 87% of the patients with pace-makers in a chronic phase from Colombia. Conclusions: In comparison with the IFA test, the ELISA-SODe-CRU yield was 85.59% sensitivity and specificity 100%. This method may be helpful for the diagnosis of Chagas disease. (C) 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.