MAPPING OF A HUMAN T-LYMPHOTROPIC VIRUS TYPE-I GAG PROTEIN EPITOPE THAT CROSS-REACTS WITH ANTI-PLASMODIUM FALCIPARUM ANTIBODIES

Studies in Palawan, Philippines, and Irian Jaya, Indonesia, showed tha t indeterminate human T-lymphotropic virus type I (HTLV-I) Western blo t immunoreactivity is due to cross-reacting anti-Plasmodium falciparum antibodies. To further define this immunoreactivity, mapping studies were conducted using the HTLV-I pig protein to identify the precise ep itope that reacts with these antibodies. Anti-P. falciparum antibody-p ositive sera from Palawan, Philippines, and Irian Jaya, Indonesia, wer e studied using overlapping synthetic peptides. Immunoreactivity was l ocalized to residues 108-120 of pig. Further analysis of the sera with 5 biotinylated synthetic peptides showed that the cross-reactive epit ope consists of the sequence PDSDPQI (amino acid residues 110-116), wh ich was shown to be homologous to a 7 amino acid sequence on the Exp-1 protein of the P. falciparum blood stage parasite. This is the first study that identifies a specific HTLV-I protein epitope that cross-rea cts with malaria antibodies. (C) 1995 Wiley-Liss, Inc.