Plasmodium vivax immunological properties of tryptophan-rich antigens PvTRAg 35 2 and PvTRAg 80 6

Need for malaria vaccine necessitates the characterization of potential antigens of the Plasmodium parasite Recently we have identified several Plasmodium vivax tryptophan-rich antigens (PvTRAgs) Here we describe the immunological characterization of hitherto undescribed two such antigens PvTRAg 35 2 and PvTRAg 80 6 which are respective homologue of Plasmodium falciparum merozoite associated tryptophan-rich antigen (PfMaTrA) and P falciparum tryptophan and threonine rich antigen (PfTryThrA) involved in erythrocyte invasion Each of the pvtrag genes is comprised of two exons where exon 2 encodes for major part of the protein PvTRAg 35 2 and PvTRAg 80 6 showed 97 06% and 94 12% (n = 34) seropositivity rates and 92 3% (n = 13) and 100% (n = 29) lymphoproliferative responses, respectively, among P vivax exposed individuals Geometric mean values of IL-12, IFN-gamma TNF alpha, IL-4 and IL-10 in PBMC culture supernatants of P vivax exposed individuals were 182 02, 60 3 62 84 196 01 and 177 17 pg/ml against PvTRAg 35 2 and 185 27 58 15 64 56 142 01 and 157 2 pg/ml against PvTRAg 80 6 showing mixed immune response with distinct biased towards anti inflammatory Th2 phenotype The pvtrag 35 2 gene was highly conserved in the parasite population whereas pvtrag 80 6 showed minor variations in the N terminal region but highly conserved in the C-terminal region containing tryptophan-rich domain (C) 2010 Institut Pasteur Published by Elsevier Masson SAS All rights reserved