Cross-species analysis of apical asparagine-rich protein of Plasmodium vivax and Plasmodium knowlesi

• Main Authors: Muh, F., Ahmed, M.A., Han, J.H., Nyunt, M.H., Lee, S.K., Lau, Y.L., Kaneko, O., Han, E.T.
• Format: Article
• Language: English
• Published: Nature Publishing Group 2018
• Subjects: R Medicine
• Online Access: http://eprints.um.edu.my/18979/1/Cross-species_analysis_of_apical_asparagine-rich_protein_of_Plasmodium_vivax_and_Plasmodium_knowlesi.pdf; http://eprints.um.edu.my/18979/; http://dx.doi.org/10.1038/s41598-018-23728-1
• Institution: Universiti Malaya

The Plasmodium falciparum apical asparagine (Asn)-rich protein (AARP) is one of malarial proteins, and it has been studied as a candidate of malaria subunit vaccine. Basic characterization of PvAARP has been performed with a focus on its immunogenicity and localization. In this study, we further analyzed the immunogenicity of PvAARP, focusing on the longevity of the antibody response, cross-species immunity and invasion inhibitory activity by using the primate malaria parasite Plasmodium knowlesi. We found that vivax malaria patient sera retained anti-PvAARP antibodies for at least one year without re-infection. Recombinant PvAARP protein was strongly recognized by knowlesi malaria patients. Antibody raised against the P. vivax and P. knowlesi AARP N-termini reacted with the apical side of the P. knowlesi merozoites and inhibited erythrocyte invasion by P. knowlesi in a concentration-dependent manner, thereby suggesting a cross-species nature of anti-PvAARP antibody against PkAARP. These results can be explained by B cell epitopes predicted in conserved surface-exposed regions of the AARP N-terminus in both species. The long-lived anti-PvAARP antibody response, cross-reactivity, and invasion inhibitory activity of anti-PvAARP support a critical role of AARP during the erythrocyte invasion and suggest that PvAARP induces long-lived cross-species protective immunity against P. vivax and P. knowlesi.