Production and Immunogenicity of a Tag-Free Recombinant Chimera Based on PfMSP-1 and PfMSP-3 Using Alhydrogel and Dipeptide-Based Hydrogels.

Gaurav Anand,Nitin Yadav,Paushali Mukherjee,Saikat Biswas,Virander Singh Chauhan

doi:10.3390/vaccines9070782

Gaurav Anand, Nitin Yadav + Show 3 more

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https://doi.org/10.3390/vaccines9070782

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Abstract

A fusion chimeric vaccine comprising multiple protective domains of different blood-stage Plasmodium falciparum antigens is perhaps necessary for widening the protective immune responses and reducing the morbidity caused by the disease. Here we continue to build upon the prior work of developing a recombinant fusion chimera protein, His-tagged PfMSP-Fu24, by producing it as a tag-free recombinant protein. In this study, tag-free recombinant PfMSPFu24 (rFu24) was expressed in Escherichia coli, and the soluble protein was purified using a three-step purification involving ammonium sulphate precipitation followed by 2-step ion exchange chromatography procedures and shown that it was highly immunogenic with the human-compatible adjuvant Alhydrogel. We further investigated two dipeptides, phenylalanine-α, β-dehydrophenylalanine (FΔF) and Leucine-α, β-dehydrophenylalanine (LΔF) based hydrogels as effective delivery platforms for rFu24. These dipeptides self-assembled spontaneously to form a highly stable hydrogel under physiological conditions. rFu24 was efficiently entrapped in both the F∆F and L∆F hydrogels, and the three-dimensional (3D) mesh-like structures of the hydrogels remained intact after the entrapment of the antigen. The two hydrogels significantly stimulated rFu24-specific antibody titers, and the sera from the immunized mice showed an invasion inhibitory activity comparable to that of Alhydrogel. Easily synthesized dipeptide hydrogels can be used as an effective antigen delivery platform to induce immune responses.

Highlights

Plasmodium falciparum malaria is one of the main causes of the high morbidity and mortality among infants and children in tropical and sub-tropical countries [1]
In this study we report that the tag-free recombinant PfMSPFu24 (rFu24) protein retained the native conformation of the PfMSP-119 component and induced invasion inhibitory antibodies in small animals as reported earlier
The PfMSPFu24 chimeric gene [30] construct excluding the 6-His tag sequence was cloned into a pET-24b vector, and the recombinant tag-free Fu24 protein was Vaccines 2021, 9, x FOR PEER REVIEWexpressed in E. coli Rosetta-gami 2(DE3) cells as a soluble protein. rFu24 was purified8 forfo1m9 the cytosolic fraction by ammonium sulphate precipitation, followed by anion-exchange chromatography and mixed mode cation-exchange chromatography (Figure 1a,b)

Summary

Introduction

Plasmodium falciparum malaria is one of the main causes of the high morbidity and mortality among infants and children in tropical and sub-tropical countries [1]. Prevailing control measures such as anti-malarial drugs and insecticides have decreased the incidence of malaria infection and reduced malaria transmission in many endemic areas. Maintaining these gains is proving to be challenging and even reversible in some areas, with an increase in resistance to drugs and insecticides. To achieve the target of eradication, better malaria vaccines will have to be designed as part of the integrated control strategy [2,5]

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