Identification of Immunodominant B-cell Epitope Regions of Reticulocyte Binding Proteins in Plasmodium vivax by Protein Microarray Based Immunoscreening.
Plasmodium falciparum can invade all stages of red blood cells, while Plasmodium vivax can invade only reticulocytes. Although many P. vivax proteins have been discovered, their functions are largely unknown. Among them, P. vivax reticulocyte binding proteins (PvRBP1 and PvRBP2) recognize and bind to reticulocytes. Both proteins possess a C-terminal hydrophobic transmembrane domain, which drives adhesion to reticulocytes. PvRBP1 and PvRBP2 are large (> 326 kDa), which hinders identification of the functional domains. In this study, the complete genome information of the P. vivax RBP family was thoroughly analyzed using a prediction server with bioinformatics data to predict B-cell epitope domains. Eleven pvrbp family genes that included 2 pseudogenes and 9 full or partial length genes were selected and used to express recombinant proteins in a wheat germ cell-free system. The expressed proteins were used to evaluate the humoral immune response with vivax malaria patients and healthy individual serum samples by protein microarray. The recombinant fragments of 9 PvRBP proteins were successfully expressed; the soluble proteins ranged in molecular weight from 16 to 34 kDa. Evaluation of the humoral immune response to each recombinant PvRBP protein indicated a high antigenicity, with 38-88% sensitivity and 100% specificity. Of them, N-terminal parts of PvRBP2c (PVX_090325-1) and PvRBP2 like partial A (PVX_090330-1) elicited high antigenicity. In addition, the PvRBP2-like homologue B (PVX_116930) fragment was newly identified as high antigenicity and may be exploited as a potential antigenic candidate among the PvRBP family. The functional activity of the PvRBP family on merozoite invasion remains unknown.
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.
Jin-Hee
JH
Han
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.|Department of Parasitology, College of Basic Medicine, Hubei University of Medicine, Shiyan, Hubei 442000, China.
Jian
J
Li
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.|Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.
Bo
B
Wang
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.
Seong-Kyun
SK
Lee
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.|Department of Medical Research, Yangon, Myanmar.
Myat Htut
MH
Nyunt
Department of Obstetrics and Gynecology, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.
Sunghun
S
Na
Department of Anatomy, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.
Jeong-Hyun
JH
Park
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea.
Eun-Taek
ET
Han
D018985:Epitopes, B-Lymphocyte / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D016780:Malaria, Vivax / Q000276:immunology / Q000469:parasitology*; D008875:Middle Aged; D010966:Plasmodium vivax / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D012156:Reticulocytes / Q000469:parasitology*
D018985:Epitopes, B-Lymphocyte; D016056:Immunodominant Epitopes; D015800:Protozoan Proteins
Plasmodium vivax; antigenicity; recombinant protein; reticulocyte binding protein