title: Production of recombinant PvDBPII, receptor binding domain of Plasmodium vivax Duffy binding protein, and evaluation of immunogenicity to identify an adjuvant formulation for vaccine development.
abstract: Plasmodium vivax is dependent on interaction with the Duffy antigen receptor for chemokines (DARC) for invasion of human erythrocytes. The P. vivax Duffy binding protein (PvDBP) mediates interaction of P. vivax merozoites with DARC. The DARC receptor-binding domain lies in a conserved N-terminal cysteine-rich region of PvDBP referred to as region II (PvDBPII). PvDBPII is an attractive vaccine candidate since antibodies raised against PvDBPII block erythrocyte invasion by P. vivax. Here, we describe methods to produce recombinant PvDBPII in its correctly folded conformation. A synthetic gene optimized for expression of PvDBPII in Escherichia coli and fed batch fermentation process based on exponential feeding strategy was used to achieve high levels of expression of recombinant PvDBPII. Recombinant PvDBPII was isolated from inclusion bodies, refolded by rapid dilution and purified by ion exchange chromatography. Purified recombinant PvDBPII was characterized for identity, purity and functional activity using standardized release assays. Recombinant PvDBPII formulated with various human compatible adjuvants including glycosylpyranosyl lipid A-stable emulsion (GLA-SE) and alhydrogel was used for immunogenicity studies in small animals to downselect a suitable formulation for clinical development. Sera collected from immunized animals were tested for recognition of PvDBPII and inhibition of PvDBPII-DARC binding. GLA-SE formulations of PvDBPII yielded higher ELISA and binding inhibition titres compared to PvDBPII formulated with alhydrogel. These data support further development of a recombinant vaccine for P. vivax based on PvDBPII formulated with GLA-SE.
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.
authors.forename: Rukmini
authors.initials: R
authors.lastname: Bhardwaj
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.
authors.forename: Ahmad Rushdi
authors.initials: AR
authors.lastname: Shakri
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.
authors.forename: Dhiraj
authors.initials: D
authors.lastname: Hans
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Gupta
authors.affiliation: Barcelona Centre for International Health (CRESIB), Barcelona, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Fernandez-Becerra
authors.affiliation: Barcelona Centre for International Health (CRESIB), Barcelona, Spain; Institució Catalana de Recerca I Estudis Avançats (ICREA), Barcelona, Spain.
authors.forename: Hernando A
authors.initials: HA
authors.lastname: Del Portillo
authors.affiliation: Malaria Vaccine Development Program (MVDP), New Delhi, India.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Pandey
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India. Electronic address: chetan.chitnis@pasteur.fr.
authors.forename: Chetan E
authors.initials: CE
authors.lastname: Chitnis
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D000071497:Immunogenicity, Vaccine; D017780:Malaria Vaccines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D010966:Plasmodium vivax / Q000235:genetics* / Q000276:immunology; D000072417:Protein Domains; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000953:Antigens, Protozoan; C066001:Duffy antigen binding protein, Plasmodium; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins
keywords: Adjuvants; Duffy binding protein; Fed-batch fermentation; Host cell invasion; Malaria vaccines; Plasmodium vivax; Protein refolding; Recombinant vaccines; Vaccine formulation