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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.