Development of Monoclonal Antibodies That Target 1-Cys Peroxiredoxin and Differentiate <i>Plasmodium falciparum</i> from <i>P. vivax</i> and <i>P. knowlesi</i>

ABSTRACT

Prompt and accurate diagnosis of malarial patients is a crucial factor in controlling the morbidity and mortality of the disease. Effective treatment decisions require a correct diagnosis among mixed-species malarial patients. Differential diagnosis is particularly important in cases of <i>Plasmodium vivax</i>, a species that shares endemicity with <i>P. falciparum</i> in most endemic areas. Moreover, it is difficult to identify <i>P. knowlesi</i> on the basis of morphology alone, and rapid diagnostic tests are still not available for this malaria species. Therefore, the development of diagnostic tests applicable to the field is urgently needed. 1-Cys peroxiredoxin (1-Cys-Prx) in <i>P. falciparum</i> is abundantly expressed in the mature asexual stages, making it a promising candidate as a diagnostic antigen. In this study, we produced five monoclonal antibodies (mAbs) against <i>P. falciparum</i> 1-Cys-Prx (Pf1-Cys-Prx) by immunizing BALB/c mice with recombinant Pf1-Cys-Prx and subsequent hybridoma production. Cross reactivity of established mAbs with the orthologous molecule of Pf1-Cys-Prx in <i>P. vivax</i> (Pv1-Cys-Prx) and <i>P. knowlesi</i> (Pk1-Cys-Prx) was examined. Western blot analyses showed that three mAbs reacted with Pv1-Cys-Prx and Pk1-Cys-Prx but two mAbs did not. These results indicate that the two mAbs were effective in differentiating <i>P. falciparum</i> from <i>P. vivax</i> and <i>P. knowlesi</i> and could be used in differential diagnosis as well as comparative molecular studies of human <i>Plasmodium</i> species.