Identification of Highly Expressed Plasmodium Vivax Proteins from Clinical Isolates Using Proteomics

Abstract

Plasmodium vivax is the most geographically widespread species responsible for malaria in humans. Our study focused on identifying highly expressed parasite proteins using a shotgun proteomics approach. Parasites (P. vivax) are isolated from seven patient samples using saponin lysis. Protein extracts from these parasites are processed and subjected to LC-MS/MS analysis. An overall proteome coverage of 605 P. vivax proteins along with 1670 human host proteins are obtained upon combining the data from LC-MS/MS runs. While a major proportion of the P. vivax proteins are either hypothetical or involved in basic cellular activities, few proteins such as tryptophan-rich antigen (Pv-fam-a; PVX_090265), Pv-fam-d protein (PVX_101520), Plasmodium exported protein (PVX_003545), Pvstp1 (PVX_094303) and hypothetical protein (PVX_083555) are detected in more than 80% of the clinical isolates and found to be unique to P. vivax without orthologs in P. falciparum. Our proteomics study on individual parasite isolates reveals highly expressed P. vivax proteins, few of which may be good candidates for vivax malaria diagnosis due to their abundance and absence in P. falciparum. This study represents the first step towards the identification of biomarkers for P. vivax malaria. In future, their clinical diagnostic values must be explored and validated on large patient cohorts.

Comprehensive proteomics investigation of P. vivax-infected human plasma and parasite isolates

“…These samples represent a small subset of the total number collected from the hospital over 2 years (n = 215). Diagnosis was performed using rapid diagnostic tests (FalciVax, Zephyr Biomedicals) and confirmed by nested PCR (Polymerase Chain Reaction) as described previously [20] (Fig. 1a).…”

“…1a). In the second year, parasites were extracted from red blood cell (RBC) pellets using 0.02% saponin lysis mentioned previously [20]. The pellets (n = 14) were snap frozen in liquid nitrogen and stored at − 80°C.…”

“…Although efforts in this direction have been promising [16] a standard in vitro culture for P. vivax has not yet been established. Hence, scientists have had to rely on clinical samples and animal models [17][18][19][20][21] for the study of P. vivax, further delaying the identification of new molecules and their functional characterization. Very recently, the proteomes of plasma-derived exosomes from P. vivax-infected FRG huHep mice were analyzed to study liver-stage expressed markers of infection.…”

Malaria in India: The Need for New Targets for Diagnosis and Detection of Plasmodium vivax

“…[30] A recent report used clinical samples to identify 605 P. vivax proteins from blood stages of the parasite, [31] while another used clinical samples and blood feeding of mosquitoes to identify over a thousand sporozoite stage proteins. [32] More recently, papers have increased the coverage of the P. vivax proteome to over a thousand proteins; however, this was possible only by injecting non-human primates with the parasite.…”

Proteomics‐Based Investigations of Neglected and Tropical Diseases

“…However, as described by Patankar et al., there are several challenges to control and eliminate P. vivax such as rapid diagnostic test (RDTs) for blood‐stage infections, inability to identify hypnozoite‐infected patients, diagnosis of G6PD deficiency, early formation of gametocytes and transmission, and markers to identify vivax disease severity. A study by Venkatesh et al . has focused on proteomics investigation of clinical isolates of P. vivax and identified candidate biomarker proteins such as tryptophan‐rich antigen from parasite.…”