Analysis of Plasmodium falciparum Rh2b deletion polymorphism across different transmission areas
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Date
2020-01-30
Journal Title
Journal ISSN
Volume Title
Publisher
Scientific Reports
Abstract
Despite significant progress in controlling malaria, the disease remains a global health burden. The
intricate interactions the parasite Plasmodium falciparum has with its host allows it to grow and
multiply in human erythrocytes. The mechanism by which P. falciparum merozoites invade human
erythrocytes is complex, involving merozoite proteins as well as erythrocyte surface proteins. Members
of the P. falciparum reticulocyte binding-like protein homolog (PfRh) family of proteins play a pivotal
role in merozoite invasion and hence are important targets of immune responses. Domains within
the PfRh2b protein have been implicated in its ability to stimulate natural protective antibodies in
patients. More specifically, a 0.58 kbp deletion, at the C-terminus has been reported in high frequencies
in Senegalese and Southeast Asian parasite populations, suggesting a possible role in immune evasion.
We analysed 1218 P. falciparum clinical isolates, and the results show that this deletion is present in
Ghanaian parasite populations (48.5% of all isolates), with Kintampo (hyper-endemic, 53.2%), followed
by Accra (Hypo-endemic, 50.3%), Cape Coast (meso-endemic, 47.9%) and Sogakope (meso-endemic,
43.15%). Further analysis of parasite genomes stored in the MalariaGEN database revealed that the
deletion variant was common across transmission areas globally, with an overall frequency of about
27.1%. Interestingly, some parasite isolates possessed mixed PfRh2b deletion and full-length alleles.
We further showed that levels of antibodies to the domain of PfRh2 protein were similar to antibody
levels of PfRh5, indicating it is less recognized by the immune system.
Description
Research Article
Keywords
Malaria, global health, immune system, antibodies