[Source: Journal of Virology, full page: (LINK). Abstract, edited.]
A measles virus-based vaccine candidate mediates protection against Zika virus in an allogenic mouse pregnancy model
Cindy Nürnberger, Bianca S. Bodmer, Anna H. Fiedler, Gülsah Gabriel, Michael D. Mühlebach
The impact of the Zika virus (ZIKV) epidemic highlights the need for vaccines that reduce or prevent infection and reliably prevent teratogenic complications. The live-attenuated measles virus (MV) vaccine strains are a promising vaccine platform since they induce robust humoral and cellular immune responses against additional antigens and have an excellent safety record. To explore its potential to protect against ZIKV, we compared a recombinant Schwarz strain MV that encodes ZIKV prM and soluble E proteins (MV-Zika-sE) with a prototypic alum-adjuvanted whole-inactivated ZIKV particle vaccine. Analysis of MV-Zika-sE-infected cells confirmed antigen expression, and the virus replicated with vaccine strain characteristics. Immunized IFNAR-/–CD46Ge mice developed E protein-specific and neutralizing antibodies, and ZIKV E-specific cellular immune responses were observed by IFN-γ ELISpot and in vitro T cell proliferation assays. To analyze protective efficacy, vaccinated female mice were challenged with ZIKV after allogenic mating. In MV-Zika-sE-vaccinated mice, weight gain was similar to uninfected mice, while no plasma viremia was detectable in the majority of the animals. In contrast, infected control animals gained less weight and experienced about 100-fold higher viremia over at least 3 days. Moreover, vaccination with MV-Zika-sE reduced ZIKV load in different organs, the placentas, and prevented infection of the fetus. Consequently, no fetal growth retardation, anemia, and death due to ZIKV infection were seen in MV-Zika-sE-vaccinated dams. In contrast, the inactivated ZIKV vaccine had little to no effect in our studies. Therefore, the MV-derived ZIKV vaccine is a promising candidate for further preclinical and clinical development.
Zika virus (ZIKV) is a mosquito-borne flavivirus, which causes a variety of neurological complications, including congenital birth defects. Despite the urgent need, no ZIKV vaccine is licensed yet. Recombinant vaccine strain-derived measles viruses (MV) constitute a promising vector platform to induce immunity against foreign pathogens by expressing antigens from additional transcription units, while at the same time possessing a remarkable safety profile. This concept has already been validated against different pathogens including at least 3 other flaviviruses, and our data illustrate that vaccination with the MV expressing soluble ZIKV E protein significantly diminishes infection and prevents fetal loss or damage in an allogenic mouse pregnancy model. It can thus be regarded as a promising emergency vaccine candidate with the potential for inclusion in routine vaccination settings in endemic areas to prevent teratogenic effects of circulating ZIKV during pregnancy, comparable to standard rubella vaccination.
Copyright © 2018 American Society for Microbiology. All Rights Reserved.
Keywords: Zika Virus; Vaccines; Animal models.