Molecular Evolution of PvMSP3α Block II in Plasmodium vivax from Diverse Geographic Origins.
Block II of Plasmodium vivax merozoite surface protein 3α (PvMSP3α) is conserved and has been proposed as a potential candidate for a malaria vaccine. The present study aimed to compare sequence diversity in PvMSP3a block II at a local microgeographic scale in a village as well as from larger geographic regions (countries and worldwide). Blood samples were collected from asymptomatic carriers of P. vivax in a village at the western border of Thailand and PvMSP3α was amplified and sequenced. For population genetic analysis, 237 PvMSP3α block II sequences from eleven P. vivax endemic countries were analyzed. PvMSP3α sequences from 20 village-level samples revealed two length variant types with one type containing a large deletion in block I. In contrast, block II was relatively conserved; especially, some non-synonymous mutations were extensively shared among 11 parasite populations. However, the majority of the low-frequency synonymous variations were population specific. The conserved pattern of nucleotide diversity in block II sequences was probably due to functional/structural constraints, which were further supported by the tests of neutrality. Notably, a small region in block II that encodes a predicted B cell epitope was highly polymorphic and showed signs of balancing selection, signifying that this region might be influenced by the immune selection and may serve as a starting point for designing multi-antigen/stage epitope based vaccines against this parasite.
Department of Entomology, Pennsylvania State University, University Park, PA 16802, United States of America.
Bhavna
B
Gupta
Department of Entomology, Pennsylvania State University, University Park, PA 16802, United States of America.
B P Niranjan
BP
Reddy
Dalian Institute of Biotechnology, Dalian, Liaoning, China.
Qi
Q
Fan
Program in Public Health, University of California, Irvine, CA 92697, United States of America.
Guiyun
G
Yan
Vector Borne Disease Training Center, Pra Budhabat, Saraburi 18120, Thailand.
Jeeraphat
J
Sirichaisinthop
Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400 Thailand.
Jetsumon
J
Sattabongkot
Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, United States of America.
Ananias A
AA
Escalante
Department of Entomology, Pennsylvania State University, University Park, PA 16802, United States of America.
Liwang
L
Cui
D000595:Amino Acid Sequence; D000953:Antigens, Protozoan / Q000235:genetics*; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010966:Plasmodium vivax / Q000235:genetics* / Q000302:isolation & purification; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics*
D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C089133:merozoite surface protein 3, Plasmodium