GENETIC DIVERSITY OF APICAL MEMBRANE ANTIGEN (AMA-1) IN ISOLATES OF PLASMODIUM VIVAX FROM BALOCHISTAN.

Abstract

Malaria is endemic in Pakistan but little research data is available on vaccine candidate antigens like Apical membrane antigen 1 (AMA-1), Circumsporozoite protein (CSP), Merozoite surface protein 1 (MSP-1) and Duffy binding protein. We found scanty information on genetic diversity of these antigen genes in Plasmodium species of Balochistan. The AMA-1 is one of the leading vaccine candidate antigen and required for the invasion of red blood cells by the malaria parasites. To the best of our knowledge, this is the first study focusing the genetic diversity of Plasmodium vivax AMA-1 (Pvama-1) gene among Pakistani isolates. The AMA-1 gene was amplified at domain-1 in 62 isolates out of 100 symptomatic clinical cases collected from Quetta, Balochistan. The amplified PCR products were further verified by sequence analysis of selected isolates. The results indicated that Plasmodium vivax showed considerable degree of polymorphism at AMA-1 gene domain-1. The comparison of PvAMA1 nucleotide sequences and resulting amino acid sequences with sequences from other countries also showed a variation. This study will serve as base line data in this region for further molecular study of this gene from other parts of country as well.