Abstract
We appreciate the interest of our colleagues in our manuscript. Our laboratory has strict control standards that guaranteed temperature stability at −20°C during the whole storage period. Frozen serum aliquots were sent by courier to the Swedish University of Agricultural Sciences with ice packs to respect the cold chain.
Other studies on IDV seroprevalence have been performed with sera stored for several years. For example, the authors reported 15 y, 13 y, and 6 y of storage.2 –4 In none of these papers is there reference to assay problems caused by storage of the sera or specifications for sampling and storage.
If we accept that some antibodies become denatured during storage, which does not seem to be the case for toxoplasma serum antibodies over at least 6 y, 1 we would have found false-negative results or, more probably, slightly lower OD values than without denaturation. That information could have been incorporated in the discussion in our manuscript. Nevertheless, our ELISA is based on whole antigen, and the antibodies measured are polyclonal, resulting in broad detection of both functional and non-functional antibodies. It is therefore unlikely that antibody denaturation at −20°C would have affected the results. Our results stand as the values that we found and reflect not only the presence of IDV antibodies in Argentina but also high seroprevalence.