Nature | Vol 585 | 24 September 2020 | 579Article
Red blood cell tension protects against
severe malaria in the Dantu blood group
Silvia N. Kariuki1,1 0, Alejandro Marin-Menendez2,1 0, Viola Introini3,1 0, Benjamin J. Ravenhill^4 ,
Yen-Chun Lin^3 , Alex Macharia^1 , Johnstone Makale^1 , Metrine Tendwa^1 , Wilfred Nyamu^1 ,
Jurij Kotar^3 , Manuela Carrasquilla^2 , J. Alexandra Rowe^5 , Kirk Rockett^6 , Dominic Kwiatkowski2,6,7,
Michael P. Weekes^4 , Pietro Cicuta3,1 1 ✉, Thomas N. Williams1,8,9,1 1 ✉ & Julian C. Rayner2,4,1 1 ✉Malaria has had a major effect on the human genome, with many protective
polymorphisms—such as the sickle-cell trait—having been selected to high
frequencies in malaria-endemic regions^1 ,^2. The blood group variant Dantu provides
74% protection against all forms of severe malaria in homozygous individuals^3 –^5 , a
similar degree of protection to that afforded by the sickle-cell trait and considerably
greater than that offered by the best malaria vaccine. Until now, however, the
protective mechanism has been unknown. Here we demonstrate the effect of Dantu
on the ability of the merozoite form of the malaria parasite Plasmodium falciparum to
invade red blood cells (RBCs). We find that Dantu is associated with extensive changes
to the repertoire of proteins found on the RBC surface, but, unexpectedly, inhibition
of invasion does not correlate with specific RBC–parasite receptor–ligand interactions.
By following invasion using video microscopy, we find a strong link between RBC
tension and merozoite invasion, and identify a tension threshold above which invasion
rarely occurs, even in non-Dantu RBCs. Dantu RBCs have higher average tension than
non-Dantu RBCs, meaning that a greater proportion resist invasion. These findings
provide both an explanation for the protective effect of Dantu, and fresh insight into
why the efficiency of P. falciparum invasion might vary across the heterogenous
populations of RBCs found both within and between individuals.The Dantu polymorphism has previously been fine-mapped to a
structural rearrangement in the glycophorin (GYP) gene cluster. The
rearrangement of the GY PA and GYPB genes creates two copies of a
hybrid gene that encodes the Dantu blood group antigen—a novel
sialoglycoprotein composed of a glycophorin B (GYPB) extracellu-
lar domain fused with a glycophorin A (GYPA) intracellular domain^5.
Both GYPA and GYPB have important functional roles in the invasion of
P. falciparum merozoites into RBCs, being receptors for the P. falcipa-
rum erythrocyte-binding ligand PfEBA-175 (ref.^6 ) and the P. falciparum
erythrocyte-binding ligand 1 (PfEBL-1)^7 , respectively.
Dantu limits invasion of red blood cells
To investigate the impact of Dantu on P. falciparum invasion, we col-
lected RBC samples from 42 healthy children from Kilifi in Kenya.
Although the prevalence of Dantu is limited geographically, being
present at much lower frequencies across Africa than the sickle
mutation in HBB (βs), it is found at a minor allele frequency (MAF) of
approximately 10% in this region—the highest yet described for this
allele^1 ,^3 , and greater than that of βs in this same area (roughly 8%)^4. To
eliminate any possible confounding influences of other large-effect
malaria-protective polymorphisms, we excluded samples from those
children with either βs or homozygous α-thalassaemia (Supplementary
Table 1). We quantified RBC invasion over one life cycle (Extended Data
Fig. 1a) using a fluorescence-activated cell sorting (FACS)-based pref-
erence assay^8. Parasites were co-cultured with differentially labelled
Dantu-heterozygous, Dantu-homozygous and non-Dantu RBCs, and
we measured invasion events into each using a fluorescent DNA dye
(Supplementary Fig. 1). We observed significantly lower invasion of
Dantu RBCs than of non-Dantu RBCs by three parasite strains (3D7, Dd2
and SAO75), and a similar but non-significant trend for strains GB4 and
7G8 (Fig. 1a), possibly because of technical variations in their growth
rates and starting parasitaemias. We chose these five strains for their
use of varying invasion pathways and their differing reliance on GYPA
in particular; Dantu limited invasion in all cases. We also observed a
trend towards greater invasion resistance by Dantu-homozygous than
Dantu-heterozygous RBCs, suggesting a dose-dependent effect (Fig. 1a
and Supplementary Table 2).
To investigate the specific step at which invasion was impaired, we
used time-lapse video microscopy to study the invasion process ofhttps://doi.org/10.1038/s41586-020-2726-6
Received: 20 November 2018
Accepted: 19 June 2020
Published online: 16 September 2020
Check for updates(^1) Department of Epidemiology and Demography, KEMRI–Wellcome Trust Research Programme, Kilifi, Kenya. (^2) Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK. (^3) Cavendish
Laboratory, University of Cambridge, Cambridge, UK.^4 Cambridge Institute for Medical Research, School of Clinical Medicine, University of Cambridge, Cambridge, UK.^5 Institute for Immunology
and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.^6 Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.^7 Big Data Institute,
University of Oxford, Oxford, UK.^8 Institute of Global Health Innovation, Imperial College London, London, UK.^9 Department of Infectious Disease, Imperial College London, London, UK.^
(^10) These authors contributed equally: Silvia N. Kariuki, Alejandro Marin-Menendez, Viola Introini. (^11) These authors jointly supervised this work: Pietro Cicuta, Thomas N. Williams, Julian C. Rayner.
✉e-mail: [email protected]; [email protected]; [email protected]