Wild isolates of Plasmodium falciparum from India show restricted polymorphism in T-helper cell epitopes of the circumsporozoite protein

Genetic polymorphism in T-helper cell epitopic regions of circumsporozoite protein of 148 Plasmodium falciparum isolates from different epidemic and endemic regions of India has been analyzed by polymerase chain reaction and sequencing. The variation has been found to be regionally unbiased in the sense that identical sequence variation has been found in different regions of India. The variation has also been found to be restricted and could be categorized into four groups. Since the variation is restricted, prototype variants could be included in a subunit polyvalent vaccine against sporozoites.