Enhanced Seroconversion to West Nile Virus Proteins in Mice by West Nile Kunjin Replicon Virus-like Particles Expressing Glycoproteins from Crimean-Congo Hemorrhagic Fever Virus

Pham-Tue-Hung Tran; Urban Höglund; Olivia Larsson; Sofia Appelberg; Ali Mirazimi; Magnus Johansson; Wessam Melik

doi:10.3390/pathogens11020233

Enhanced Seroconversion to West Nile Virus Proteins in Mice by West Nile Kunjin Replicon Virus-like Particles Expressing Glycoproteins from Crimean-Congo Hemorrhagic Fever Virus

Pathogens. 2022 Feb 10;11(2):233. doi: 10.3390/pathogens11020233.

Authors

Pham-Tue-Hung Tran¹, Urban Höglund², Olivia Larsson², Sofia Appelberg³, Ali Mirazimi^{4

5}, Magnus Johansson¹, Wessam Melik¹

Affiliations

¹ School of Medical Science, Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, 703 62 Örebro, Sweden.
² Adlego Biomedical AB, P.O. Box 42, 751 03 Uppsala, Sweden.
³ Department of Microbiology, Public Health Agency of Sweden, 171 82 Solna, Sweden.
⁴ Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institution, 141 52 Huddinge, Sweden.
⁵ National Veterinary Institute, 751 89 Uppsala, Sweden.

Abstract

Removal of genes coding for major parts of capsid (C), premembrane (prM), and envelope (E) proteins on the flavivirus genome aborts the production of infectious virus particles where the remaining genome forms a replicon that retains replicability in host cells. The C-prM-E proteins can also be expressed in trans with the flavivirus replicons to generate single-round infectious replicon virus-like particles (RVPs). In this study, we characterized the use of RVPs based on the Kunjin strain of WNV (WNV_KUN) as a putative WNV vaccine candidate. In addition, the WNV_KUN C-prM-E genes were substituted with the Crimean-Congo hemorrhagic fever virus (CCHFV) genes encoding the glycoproteins Gn and Gc to generate a WNV_KUN replicon expressing the CCHFV proteins. To generate RVPs, the WNV_KUN replicon was transfected into a cell line expressing the WNV_KUN C-prM-E. Using immunoblotting and immunofluorescence assays, we showed that the replicon can express the CCHFV Gn and Gc proteins and the RVPs can transduce cells to express WNV_KUN proteins and the CCHFV Gn and Gc proteins. Our study also revealed that these RVPs have potential as a vaccine platform with low risk of recombination as it infects cells only in one cycle. The immunization of mice with the RVPs resulted in high seroconversion to both WNV E and NS1 but limited seroconversion to CCHFV Gn and Gc proteins. Interestingly, we found that there was enhanced production of WNV E, NS1 antibodies, and neutralizing antibodies by the inclusion of CCHFV Gc and Gn into WNV_KUN RVPs. Thus, this study indicates a complementary effect of the CCHFV Gn and Gc proteins on the immunogenicity by WNV_KUN RVPs, which may be applied to develop a future vaccine against the WNV.

Keywords: Crimean–Congo hemorrhagic fever virus; West Nile Kunjin virus; envelope; glycoprotein (Gn–Gc); neutralization; non-structural protein 1; replicon virus-like particles (RVPs); replicons; seroconversion; vaccines.

Abstract

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