PfEMP1 A-type ICAM-1-binding domains are not associated with cerebral Malaria in Beninese children

2020

Article référencé dans le Web of Science WOS:000613614600012

Joste V., Guillochon E., Fraering Jeremy, Vianou B., Watier L., Guemouri Sayeh, Cot Michel, Houze S., Aubouy Agnès, Faucher J. F., Argy N., Bertin Gwladys, NeuroCM Study Group

Mbio, 2020, 11 (6), e02103-20 [14 p.] ISSN 2150-7511

PfEMP1 is the major antigen involved in Plasmodium falciparum-infected erythrocyte sequestration in cerebrovascular endothelium. While some PfEMP1 domains have been associated with clinical phenotypes of malaria, formal associations between the expression of a specific domain and the adhesion properties of clinical isolates are limited. In this context, 73 cerebral malaria (CM) and 98 uncomplicated malaria (UM) Beninese children were recruited. We attempted to correlate the cytoadherence phenotype of Plasmodium falciparum isolates with the clinical presentation and the expression of specific PfEMP1 domains. Cytoadherence level on Hbec-5i and CHO-ICAM-1 cell lines and var genes expression were measured. We also investigated the prevalence of the ICAM-1-binding amino acid motif and dual receptor-binding domains, described as a potential determinant of cerebral malaria pathophysiology. We finally evaluated IgG levels against PfEMP1 recombinant domains (CIDR alpha 1.4, DBL beta 3, and CIDR alpha 1.4-DBL beta 3). CM isolates displayed higher cytoadherence levels on both cell lines, and we found a correlation between CIDR alpha 1.4 DBL beta 1/3 domain expression and CHO-ICAM-1 cytoadherence level. Endothelial protein C receptor (EPCR)-binding domains were overexpressed in CM isolates compared to UM whereas no difference was found in ICAM-1-binding DBL beta 1/3 domain expression. Surprisingly, both CM and UM isolates expressed ICAM-1-binding motif and dual receptor-binding domains. There was no difference in IgG response against DBL beta 3 between CM and UM isolates expressing ICAM-1-binding DB4 beta/3 domain. It raises questions about the role of this motif in CM pathophysiology, and further studies are needed, especially on the role of DBL beta 1/3 without the ICAM-1-binding motif. IMPORTANCE Cerebral malaria pathophysiology remains unknown despite extensive research. PfEMP1 proteins have been identified as the main Plasmodium antigen involved in cerebrovascular endothelium sequestration, but it is unclear which var gene domain is involved in Plasmodium cytoadhesion. EPCR binding is a major determinant of cerebral malaria whereas the ICAM-1-binding role is still questioned. Our study confirmed the EPCR-binding role in CM pathophysiology with a major overexpression of EPCR-binding domains in CM isolates. In contrast, ICAM-1-binding involvement appears less obvious with A-type ICAM-1-binding and dual receptor-binding domain expression in both CM and UM isolates. We did not find any variations in ICAM-1-binding motif sequences in CM compared to UM isolates. UM and CM patients infected with isolates expressing the ICAM-1-binding motif displayed similar IgG levels against DBL beta 3 recombinant protein. Our study raises interrogations about the role of these domains in CM physiopathology and questions their use in vaccine strategies against cerebral malaria.

Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Santé : généralités [050] ; Entomologie médicale / Parasitologie / Virologie [052]

BENIN

Fonds IRD [F B010080902]

fdi:010080902