Proteome-wide characterization of Plasmodium vivax antigens using a high-density peptide array

Plasmodium vivax is the second most prevalent Plasmodium species, with 2.5 billion people at risk of infection worldwide and around 10 million cases of clinical vivax malaria every year. Despite the clinical importance of this pathogen, little is known about the P. vivax proteins recognized by the host immune system, which hinders our ability to select vaccine candidates or to develop efficient serological markers. To characterize immunogenic P. vivax proteins, we designed a high-density peptide array containing 4.2 million peptides covering the entire protein sequences of all P. vivax genes and analyzed antibody responses of infected and malaria-naïve individuals. We identified a total of 283 proteins that are commonly immunogenic in symptomatic individuals. These proteins included many proteins known to be involved in erythrocyte invasion, several nucleoporins, and many uncharacterized proteins that should be further investigated for their roles during blood-stage infections. These analyses also revealed a unique pattern of antibody response against PIR proteins in asymptomatic individuals that could be associated with protection against clinical vivax malaria. Overall, these data provide an agnostic and proteome-wide perspective on immunogenic P. vivax proteins and constitute an important resource for the malaria community to develop new tools for better detecting and eliminating this important human pathogen.