Identification and characterization of the Plasmodium vivax thrombospondin-related apical merozoite protein

• Published in: Malaria Journal
• Main Authors: Villarreal-Gonzalez Silvana, Moreno-Perez Darwin A, Angel Diana I, Mongui Alvaro, Almonacid Hannia, Vanegas Magnolia, Patarroyo Manuel A
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2010
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Pacific
• Online Access: https://doi.org/10.1186/1475-2875-9-283; https://doaj.org/article/54bc597642b840ff94d6c7f956a98e69

Abstract Background Malaria caused by Plasmodium vivax is a major public health problem worldwide that affects 70-80 million people in the Middle East, Asia, Western Pacific, South America and the Caribbean. Despite its epidemiological importance, few antigens from this parasite species have been characterized to date compared to Plasmodium falciparum , due in part to the difficulties of maintaining an in vitro culture of P. vivax . This study describes the identification of the P. falciparum thrombospondin-related apical merozoite protein homologue in P. vivax (PvTRAMP) and examines its potential to be further evaluated as vaccine candidate. Methods The gene encoding PvTRAMP was identified through an extensive search of the databases hosting the genome sequence of P. vivax . Genes adjacent to pvtramp were identified in silico to determine the degree of similarity between the protein sequences encoded by equivalent chromosomic fragments in P. falciparum and Plasmodium knowlesi . The pvtramp gene was amplified from cDNA of P. vivax schizont stages, cloned and expressed in Escherichia coli . Anti-PvTRAMP antisera was obtained by inoculating rabbits with PvTRAMP B cell epitopes produced as synthetic peptides in order to assess its recognition in parasite lysates by Western blot and in intact parasites by indirect immunofluorescence. The recognition of recombinant PvTRAMP by sera from P. vivax- infected individuals living in endemic areas was also assessed by ELISA. Results The PfTRAMP homologue in P. vivax , here denoted as PvTRAMP, is a 340-amino-acid long antigen encoded by a single exon that could have a potential role in cytoadherence, as indicated by the presence of a thrombospondin structural homology repeat (TSR) domain. According to its transcription and expression profile, PvTRAMP is initially located at the parasite's apical end and later on the parasite surface. Recombinant PvTRAMP is recognized by sera from infected patients, therefore, indicating that it is targeted by the immune system during a ...