Geographic origin of the samples used for genomic studies of <i>PFI1785w</i>.

<p>Geographic origin of the samples used for genomic studies of <i>PFI1785w</i>.</p

Skyline output and calibration range for GHTVDSELTTEDPVIQKK.

<p>Retention time is displayed on x axis and intensity for each ion or fragment is displayed on y axis. Each parent ion and fragment is shown in a different colour. AUC corresponds to the integration of signal under the curve (A). Regression line is obtained using AUC from each concentration point.</p

Linear regression line obtained with Skyline integration of raw files.

<p>Linear regression line obtained with Skyline integration of raw files.</p

Secondary structure of PFI1785w predicted using Phyre 2 and predictive 3D structure of amino-acid 224–360.

<p>Secondary structure of PFI1785w predicted using Phyre 2 and predictive 3D structure of amino-acid 224–360.</p

Peptide concentration measured within calibration range of each peptide.

<p>Peptide concentrations calculated by linear regression for each studied protein, y axis presents peptide concentration. Each dot represents one sample, and reference strains are displayed separately on the right of each plot (CSA+: CSA adhesion selected parasite strain, CSA-: non selected parasite strain). PAM samples and CSA+ parasite strains display a placental malaria like binding phenotype (in red), and UM samples and CSA- parasite strain display a uncomplicated malaria phenotype (in blue). PF14_0018, PFA_0410w, PFB0115w and PFI1785w are preferentially found in PAM like samples.</p

Expression of the Domain Cassette 8 <i>Plasmodium falciparum</i> Erythrocyte Membrane Protein 1 Is Associated with Cerebral Malaria in Benin

<div><p>Background</p><p><i>Plasmodium falciparum</i> erythrocyte membrane protein-1 (<i>Pf</i>EMP-1) is a highly polymorphic adherence receptor expressed on the surface of infected erythrocytes. Based on sequence homology <i>Pf</i>EMP-1 variants have been grouped into three major groups A-C, the highly conserved VAR2CSA variants, and semi-conserved types defined by tandem runs of specific domains (“domain cassettes” (DC)). The <i>Pf</i>EMP-1 type expressed determines the adherence phenotype, and is associated with clinical outcome of infection.</p><p>Methods</p><p>Parasite isolates from Beninese children or women presenting with, respectively, CM or PAM were collected along with samples from patients with uncomplicated malaria (UM). We assessed the transcript level of <i>var</i> genes by RT-qPCR and the expression of PfEMP-1 proteins by LC-MS/MS.</p><p>Results</p><p><i>Var</i> genes encoding DC8 and Group A <i>Pf</i>EMP-1 were transcribed more often and at higher levels in cerebral malaria <i>vs.</i> uncomplicated malaria patients. LC-MS/MS identified peptides from group A, DC8 <i>Pf</i>EMP-1 more frequently in cerebral malaria than in uncomplicated malaria and pregnancy-associated malaria samples.</p><p>Conclusion</p><p>This is the first study to show association between <i>Pf</i>EMP-1 subtype and disease outcome by direct analysis of parasites proteome. The results corroborate that group A and specifically the <i>Pf</i>EMP-1 types DC8 are universally associated with cerebral malaria. This is a crucial observation for promoting studies on malaria pathogenesis.</p></div

<i>Var</i> gene transcript levels and <i>Pf</i>EMP-1 proteins identified in the samples collected from patients with cerebral malaria.

<p>Each line corresponds to one sample, the right axis shows <i>var</i> genes transcription levels for each sample and the left axis shows the proteins identified by LC-MS/MS.</p

List of primers used for RT-qPCR [20].

<p>The primers targeted the indicated domain subclasses. Some domains occur in domain cassettes and all can be associated to a <i>Pf</i>EMP-1 UPS grouping.</p

Proportion of proteins identified by LC-MS/MS in parasite samples in Benin, by clinical group.

<p>Cerebral malaria (CM, circle), pregnancy-associated malaria (PAM, triangle), and uncomplicated malaria (UM, diamond). Each data point represents the proportion of proteins associated to each UPS group among all <i>Pf</i>EMP-1 proteins, for one patient. Bars indicate median with interquartile range. (*) shows a difference between CM vs PAM <i>P</i> = 0.017. (**) shows a difference between PAM vs CM and vs UM <i>P</i> = 0.0085, <i>P</i> = 0.0190 respectively.</p

<i>Var</i> type transcription in samples from patients with cerebral and uncomplicated malaria in Benin.

<p>White boxes show transcript units (Tu) <2; light-grey box: 250. Statically significant higher transcript levels in patients with cerebral malaria than in patients with uncomplicated malaria is indicated by (*) p≤0,05; (**) p≤0,01; (***) p≤10⁻³. Statistically significant higher transcript level among patients with uncomplicated malaria compared to patients with malaria cerebral is indicated as (+) p≤10⁻³.</p