A novel approach based on antigen, antibody and immune complex detection in bronchoalveolar lavage fluid samples from rats experimentally infected with Strongyloides venezuelensis

This study was performed in order to develop a novel approach based on antigen, antibody and immune complex detection by enzyme-linked immunosorbent assay (ELISA) in bronchoalveolar lavage fluid (BALF) samples. For that purpose Wistar rats immunosuppressed or not were experimentally infected with Strongyloides venezuelensis. The microtiter plates were coated with alkaline parasite extract for antibody detection and with IgG anti-S. venezuelensis for antigen and immune complex detection. The immune serum was able to detect 1.56 μg/mL of L3 antigens in BALF samples. ELISA sensitivity was 96.6%, 71.6% and 91.6% for antigen, antibody and immune complex, respectively, and the specificity was 100% for all methods. Antigen detection in BALF samples showed to be a good approach for evaluating the kinetics of infection in non immunosuppressed or immunosuppressed rats. IgG was detected in non immunosuppressed rats from day 8 p.i. and in immunosuppressed rats from day 2 p.i. Moreover, immune complex was detected during the entire kinetic for both groups. In conclusion, association of antigen, antibody and immune complex detection in BALF samples seems to be an alternative approach for early strongyloidiasis diagnosis particularly in immunosuppressed individuals.