Immunization with DNA plasmids coding for crimean-congo hemorrhagic fever virus capsid and envelope proteins and/or virus-like particles induces protection and survival in challenged mice

Jorma Hinkula, Stéphanie Devignot, Sara Åkerström, Helen Karlberg, Eva Wattrang, Sándor Bereczky, Mehrdad Mousavi-Jazi, Christian Walter Risinger, Gunnel Lindegren, Caroline Vernersson, Janusz Paweska, Petrus Jansen van Vuren, Klas Ola Blixt, Alejandro Brun, Weber Friedemann, Ali Mirazimi*

*Corresponding author for this work
32 Citations (Scopus)
97 Downloads (Pure)

Abstract

Crimean-Congo hemorrhagic fever virus (CCHFV) is a bunyavirus causing severe hemorrhagic fever disease in humans, with high mortality rates. The requirement of a high-containment laboratory and the lack of an animal model hampered the study of the immune response and protection of vaccine candidates. Using the recently developed interferon alpha receptor knockout (IFNAR-/-) mouse model, which replicates human disease, we investigated the immunogenicity and protection of two novel CCHFV vaccine candidates: a DNA vaccine encoding a ubiquitin-linked version of CCHFV Gc, Gn, and N and one using transcriptionally competent virus-like particles (tc-VLPs). In contrast to most studies that focus on neutralizing antibodies, we measured both humoral and cellular immune responses. We demonstrated a clear and 100% efficient preventive immunity against lethal CCHFV challenge with the DNA vaccine. Interestingly, there was no correlation with the neutralizing antibody titers alone, which were higher in the tc-VLP-vaccinated mice. However, the animals with a lower neutralizing titer, but a dominant cell-mediated Th1 response and a balanced Th2 response, resisted the CCHFV challenge. Moreover, we found that in challenged mice with a Th1 response (immunized by DNA/DNA and boosted by tc-VLPs), the immune response changed to Th2 at day 9 postchallenge. In addition, we were able to identify new linear B-cell epitope regions that are highly conserved between CCHFV strains. Altogether, our results suggest that a predominantly Th1-type immune response provides the most efficient protective immunity against CCHFV challenge. However, we cannot exclude the importance of the neutralizing antibodies as the surviving immunized mice exhibited substantial amounts of them.

Original languageEnglish
Article numbere02076-16
JournalJournal of Virology
Volume91
Issue number10
Number of pages19
ISSN0022-538X
DOIs
Publication statusPublished - 2017

Keywords

  • Crimean-Congo hemorrhagic fever virus
  • DNA vaccines
  • Neutralizing antibodies
  • Th1/Th2 responses
  • VLP

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