Characterising PvRBSA: an exclusive protein from Plasmodium species infecting reticulocytes

Abstract

Background Plasmodium vivax uses multiple ligand-receptor interactions for preferential invasion of human reticulocytes. Several of these ligands have been identified by in silico approaches based on the role displayed by their orthologs in other Plasmodium species during initial adhesion or invasion. However, the cell adhesion role of proteins that are exclusive to species that specifically invade reticulocytes (as P. vivax and P. cynomolgi) has not been evaluated to date. This study aimed to characterise an antigen shared between Plasmodium species that preferentially infect reticulocytes with a focus on assessing its binding activity to target cells.ResultsAn in silico analysis was performed using P. vivax proteome data to identify and characterise one antigen shared between P. vivax and P. cynomolgi. This led to identification of the pvrbsa gene present in the P. vivax VCG-I strain genome. This gene is transcribed in mature schizonts and encodes a protein located on the parasite surface. rPvRBSA was antigenic and capable of binding to a population of reticulocytes with a different Duffy phenotype. Interestingly, the molecule showed a higher percentage of binding to immature human reticulocytes (CD71hi).ConclusionsThis study describes for the first time, a molecule involved in host cell binding that is exclusive in reticulocyte-infecting Plasmodium species. This suggest that PvRBSA is an antigenic adhesin that plays a role in parasite binding to target cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2185-6) contains supplementary material, which is available to authorized users.

On the Evolution and Function of Plasmodium vivax Reticulocyte Binding Surface Antigen (pvrbsa)

“…One antigen shared just by P. vivax and P. cynomolgi (both having reticulocyte predilection) has been characterized recently ( Moreno-Perez et al, 2017 ). This antigen (named reticulocyte binding surface antigen – RBSA) is encoded by a two-exon gene ( Moreno-Perez et al, 2017 ) located on Chr 3. The protein product has a signal peptide and two transmembrane helices and is located on mature Mrz membrane.…”

“…This protein seems to be involved in Mrz invasion, since recombinant P. vivax RBSA (rPvRBSA) binds to a subpopulation of immature reticulocytes having a Duffy positive phenotype; it is also recognized by the human immune system in natural infections. It has thus been suggested as a putative vaccine candidate for anti- P. vivax malaria vaccine development ( Moreno-Perez et al, 2017 ).…”

Receptor-ligand and parasite protein-protein interactions inPlasmodium vivax: Analysing rhoptry neck proteins 2 and 4

“…described protocols(Arevalo-Pinzon et al, 2017;Moreno-Perez, Baquero, Chitiva-Ardila, & Patarroyo, 2017).Briefly, or PvRON2-RI recombinant protein were incubated with 5% UCB RBC and then incubated with antibodies against the transferrin receptor (CD71) on reticulocytes, against cluster of differentiation 45 (CD45) in leukocytes (some activated leukocytes are CD71 + , but reticulocytes are CD45 − , so the reticulocyte population selected was CD71 + CD45 − ) and antibodies against the 6X-His-tag in recombinant proteins. UCB RBC were preincubated with peptides before adding recombinant protein for competition assays with peptides 40305 and 40595.…”

Plasmodium vivax Cell Traversal Protein for Ookinetes and Sporozoites (CelTOS) Functionally Restricted Regions Are Involved in Specific Host-Pathogen Interactions

“…Protein expression was induced by adding 0.2% L-arabinose and incubating at 37 • C for 4 h at 250 rpm. The culture was spun at 4,500 rpm for 20 min; the pellet was then suspended in solubilising buffer (Moreno-Perez et al, 2017), lysozyme and a protease inhibitor cocktail (Thermo Fisher), as previously described. This mixture was incubated overnight at 10 rpm using a tube rotator (Fisher Scientific, Waltham, USA).…”