Production and Preclinical Evaluation of Plasmodium falciparum MSP-1 ₁₉ and MSP-3 ₁₁ Chimeric Protein, PfMSP-Fu ₂₄

Abstract

A Plasmodium falciparum chimeric protein, PfMSP-Fu 24 , was constructed by genetically coupling immunodominant, conserved regions of two merozoite surface proteins, the 19-kDa region C-terminal region of merozoite surface protein 1 (PfMSP-1 19 ) and an 11-kDa conserved region of merozoite surface protein 3 (PfMSP-3 11 ), to augment the immunogenicity potential of these blood-stage malaria vaccine candidates. Here we describe an improved, efficient, and scalable process to produce high-quality PfMSP-Fu 24 . The chimeric protein was produced in Escherichia coli SHuffle T7 Express lysY cells that express disulfide isomerase DsbC. A two-step purification process comprising metal affinity followed by cation exchange chromatography was developed, and we were able to obtain PfMSP-

Carbomer-based Nano-Emulsion Adjuvant Enhances Dendritic Cell Cross-presentation via Lipid Body Formation Independent of Glycolysis

“…There is high level of interest in developing adjuvants that can stimulate potent CD8 and CD4 T cell responses to subunit antigens. Carbomer (acrylic acid polymers)-based adjuvants (CBA) are components of several veterinary vaccines, and known to safely elicit potent neutralizing antibodies to malarial and HIV envelope glycoproteins in mice and nonhuman primates (Menon et al, 2015, Gupta et al, 2014, Anlar et al, 1993. We have also reported that the carbomer-based nano-emulsion adjuvant, Adjuplex (ADJ; Advanced Bioadjuvants), elicits tissue-resident memory CD8 T cells in the lungs, and protects against influenza A virus in mice (Gasper et al, 2016).…”

Antigenicity of a Bacterially Expressed Triple Chimeric Antigen of Plasmodium falciparum AARP, MSP-311 and MSP-119: PfAMSP-Fu35

“…However, lack of such an antigenic competition has been reported earlier for other malaria fusion proteins [23,24,27,33]. These results highlight the potential of the approach of using fusion chimeras comprised of key antigenic determinants of different antigens for subunit vaccine development.…”

“…First, the protein was expressed and purified with ease in relatively higher yields than its individual components; PfMSP-3 11 was purified from inclusion bodies and yields of soluble PfMSP-1 19 were low [27,33]. Second, the conformational integrity of PfMSP-1 19 fragment was maintained which is essential for producing invasion inhibitory antibodies to this fragment.…”

“…Constituent protein fragments of AMSP-Fu 35 , namely PfAARP, PfMSP-3 11 and PfMSP-1 19 were prepared by recombinant methods which were purified and characterized as described earlier [21,33]. …”

“…The fragments PfMSP-3 11 of PfMSP-3 and PfMSP-1 19 of PfMSP-1 were used in this fusion construct because of their following advantages: i) PfMSP-3 11 , the 70 amino acid fragment of PfMSP-3 is known to possess T helper epitopes to which high levels of cytophilic antibodies have been directed [28]; ii) In combination with GLURP, N-terminal region of PfMSP-3 induced high titre antibodies and memory B cells [23]; iii) highly conserved PfMSP-1 19 fragment neutralized merozoites, inhibited parasite invasion in vitro and reduced parasitemia and disease severity in vivo [29]; iv) fusion of PfMSP-3 11 to PfMSP-1 19 raised the titre of inhibitory antibodies specific to PfMSP-1 19 [27,33]; v) in combinations with other blood stage antigens both the fragments have been involved in clinical trials [34]. …”