Characterizing Pv ARP, a novel Plasmodium vivax antigen

• Published in: Malaria journal 2013-05, Vol.12 (1), Article 165
• Main Authors: Moreno-Pñrez, Darwin A, Saldarriaga, Ambar, Patarroyo, Manuel A
• Format: Article
• Language: English
• Subjects: Antibodies; Antigens; Asparagine; Cell adhesion & migration; Disease; Genes; Genetic transcription; Health aspects; Infections; Laboratory animals; Malaria; Medical research; Medicine, Experimental; Molecular biology; Monkeys & apes; Mortality; Prevention; Proteins; Risk factors; Software; Studies; Tropical diseases; Viral antibodies
• ISSN: 1475-2875; 1475-2875
• DOI: 10.1186/1475-2875-12-165

Background Plasmodium vivax continues to be the most widely distributed malarial parasite species in tropical and sub-tropical areas, causing high morbidity indices around the world. Better understanding of the proteins used by the parasite during the invasion of red blood cells is required to obtain an effective vaccine against this disease. This study describes characterizing the P. vivax asparagine-rich protein (Pv ARP) and examines its antigenicity in natural infection. Methods The target gene in the study was selected according to a previous in silico analysis using profile hidden Markov models which identified P. vivax proteins that play a possible role in invasion. Transcription of the arp gene in the P. vivax VCG-1 strain was here evaluated by RT-PCR. Specific human antibodies against Pv ARP were used to confirm protein expression by Western blot as well as its subcellular localization by immunofluorescence. Recognition of recombinant Pv ARP by sera from P. vivax- infected individuals was evaluated by ELISA. Results VCG-1 strain Pv ARP is a 281-residue-long molecule, which is encoded by a single exon and has an N-terminal secretion signal, as well as a tandem repeat region. This protein is expressed in mature schizonts and is located on the surface of merozoites, having an apparent accumulation towards their apical pole. Sera from P. vivax-infected patients recognized the recombinant, thereby suggesting that this protein is targeted by the immune response during infection. Conclusions This study showed the characterization of Pv ARP and its antigenicity. Further assays orientated towards evaluating this antigen's functional importance during parasite invasion are being carried out. Keywords: Plasmodium vivax, Protein, Invasion, Antigenicity, Vaccine