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

Abstract

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.

Keywords

• Plasmodium vivax
• Apical membrane antigen
• Iran