Sequence Analysis of Different Domains of Plasmodium vivax Apical Membrane Antigen (PvAMA-1 gene) Locus in Iran

Plasmodium vivax is responsible for approximately 80 million malaria cases in the world. Apical membrane antigen1 (AMA-1) is a type I integral membrane protein present in all Plasmo­dium species. AMA-1 interferes in critical steps of invasion of human hepatocytes by sporo­zoites and red blood cells by merozoites and is one of the most immunodominant antigens for elicit­ing a protective immune response in human. It is considered as a promising antigen for inclusion in a vaccine against P. vivax. Since more knowledge is needed to lighten the scope of such antigen we com­pared genetic variation in P. vivax AMA-1from an Iranian isolate with those reported from some of the other malarious countries so far. P. vivax genomic DNA was extracted from the whole blood of an Iranian patient with pa­tent P. vivax infection. The nucleotide sequence for 446 amino acid (AA) residues (42-488 of PvAMA-1) was amplified by PCR and cloned in pUC19 vector for sequencing. Sequence analysis of the antigen showed a high degree of identity (99%) with strong homol­ogy to the PvAMA-1 gene of P. vivax S3 and SKO814 isolates from India and Korea (Asian isolates) respectively, and 96% similarity with P. vivax Sal-1 AMA-1 gene from El Salvador. We cloned and characterized three domains of PvAMA-1 gene from an Iranian patient. Predicted protein sequence of this gene showed some discrepancies in corresponding protein in compar­ing with similar genes reported from other malarious countries.