Plasmodium vivax: Polymorphism in the merozoite surface protein 1 gene from wild Colombian isolates

The Plasmodium vivax merozoite surface protein-1 (PvMSP-1) has been conside red a candidate for a malaria vaccine against erythrocytic stages. PvMSP-1 is immunogenic during natural infections and exhibits antigenic polymorphis m. The extent of genetic polymorphism in a region between the so-called int erspecies conserved blocks (ICBs) 2 and 4 of the PvMSP-1 was analyzed in 20 isolates taken from patients from two different areas in Colombia. Variati on is unevenly distributed along this gene segment among the isolates. Comp arative analysis of these sequences led to the definition of five sequence types (ST1 to 5). ST1 to ST4 exhibit a variation pattern associated with se quences present in the Salvador or Belem sequences. However, ST5 has cluste rs of sequence that have not been previously described. The changes found a long the five variants confirm the important role of recombinational and/or gene conversion events in generating allelic diversity. (C) 2000 Academic Press.