Two 20-Residue-Long Peptides Derived from Plasmodium vivax Merozoite Surface Protein 10 EGF-Like Domains Are Involved in Binding to Human Reticulocytes.

Affiliation

Ricaurte-Contreras LA(1)(2), Lovera A(1), Moreno-Pérez DA(1), Bohórquez MD(1), Suárez CF(3), Gutiérrez-Vásquez E(1), Cuy-Chaparro L(1), Garzón-Ospina D(1), Patarroyo MA(1)(4)(5).
Author information:
(1)Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia
(FIDIC), Carrera 50#26-20, Bogotá 111321, Colombia.
(2)MSc Programme in Microbiology, Universidad Nacional de Colombia, Carrera 45#26-85, Bogotá 111321, Colombia.
(3)Biomathematics Department, Fundación Instituto de Inmunología de Colombia
(FIDIC), Carrera 50#26-20, Bogotá 111321, Colombia.
(4)Health Sciences Division, Main Campus, Universidad Santo Tomás, Carrera 9#51-11, Bogotá 110231, Colombia.
(5)Microbiology Department, Faculty of Medicine, Universidad Nacional de Colombia, Carrera 45#26-85, Bogotá 111321, Colombia.

Abstract

Plasmodium parasites' invasion of their target cells is a complex, multi-step process involving many protein-protein interactions. Little is known about how complex the interaction with target cells is in Plasmodium vivax and few surface molecules related to reticulocytes' adhesion have been described to date. Natural selection, functional and structural analysis were carried out on the previously described vaccine candidate P. vivax merozoite surface protein 10 (PvMSP10) for evaluating its role during initial contact with target cells. It has been shown here that the recombinant carboxyl terminal region (rPvMSP10-C) bound to adult human reticulocytes but not to normocytes, as validated by two different protein-cell interaction assays. Particularly interesting was the fact that two 20-residue-long regions (388DKEECRCRANYMPDDSVDYF407 and 415KDCSKENGNCDVNAECSIDK434) were able to inhibit rPvMSP10-C binding to reticulocytes and rosette formation using enriched target cells. These peptides were derived from PvMSP10 epidermal growth factor (EGF)-like domains (precisely, from a well-defined electrostatic zone) and consisted of regions having the potential of being B- or T-cell epitopes. These findings provide evidence, for the first time, about the fragments governing PvMSP10 binding to its target cells, thus highlighting the importance of studying them for inclusion in a P. vivax antimalarial vaccine.