Oral Presentation First Malaria World Congress 2018

A truncated reticulocyte binding protein from p. vivax: functional characteristics and antibody response (#215)

Wang Nguitragool 1
  1. Mahidol University, Ratchathewi, Bangkok, Thailand

Erythrocyte binding ligands of malaria parasites are key targets in vaccine development to inhibit red blood cell invasion. The P. vivax genome encodes several such proteins, including two Duffy Binding Proteins (PvDBPs) and several Reticulocyte Binding Proteins (PvRBPs). Here we explore the role of a novel PvRBP, PvRBP-2P1. PvRBP-2P1 is encoded by a truncated gene in the parasite genome and contains only the N-terminal binding domain, much like the vaccine candidate PfRH5 of P. falciparum. PvRBP-2P1 is expressed in all parasite isolates tested. Its specific expression in merozoite and erythrocyte binding activity are consistent with a role in invasion. Interestingly, the antibody level to PvRBP-2P1 is associated with lower parasitemia in P. vivax malaria patients. Infected asymptomatic carriers also tend to have higher antibodies than do patients. Together these data suggest a protective role of anti-PvRBP-2P1 antibodies, possibly through inhibition of erythrocyte invasion.