Reticulocyte and erythrocyte binding-like proteins function cooperatively in invasion of human erythrocytes by malaria parasites

Sash Lopaticki, Alexander Gerd Maier, Jennifer Thompson, Danny W Wilson, Wai Hong Tham, Tony Triglia, Alex Gout, Terence P Speed, James G. Beeson, Julie Healer, Alan Frederick Cowman

Research output: Contribution to journalArticleResearchpeer-review

100 Citations (Scopus)

Abstract

Plasmodium falciparum causes the most severe form of malaria in humans and invades erythrocytes using multiple ligand-receptor interactions. Two important protein families involved in erythrocyte binding are the erythrocyte binding-like (EBL) and the reticulocyte binding-like (RBL or P. falciparum Rh [PfRh]) proteins. We constructed P. falciparum lines lacking expression of EBL proteins by creating single and double knockouts of the corresponding genes for eba-175, eba-181, and eba-140 and show that the EBL and PfRh proteins function cooperatively, consistent with them playing a similar role in merozoite invasion. We provide evidence that PfRh and EBL proteins functionally interact, as loss of function of EBA-181 ablates the ability of PfRh2a/b protein antibodies to inhibit merozoite invasion. Additionally, loss of function of some ebl genes results in selection for increased transcription of the PfRh family. This provides a rational basis for considering PfRh and EBL proteins for use as a combination vaccine against P. falciparum. We immunized rabbits with combinations of PfRh and EBL proteins to test the ability of antibodies to block merozoite invasion in growth inhibition assays. A combination of EBA-175, PfRh2a/b, and PfRh4 recombinant proteins induced antibodies that potently blocked merozoite invasion. This validates the use of a combination of these ligands as a potential vaccine that would have broad activity against P. falciparum.

Original languageEnglish
Pages (from-to)1107-1117
Number of pages11
JournalInfection and Immunity
Volume79
Issue number3
DOIs
Publication statusPublished - Mar 2011
Externally publishedYes

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