Across the developing world peste des petits ruminants virus (PPRV) places a huge disease burden on small ruminant agriculture. PPR is mainly controlled by vaccinating animals with live attenuated vaccines. However, the current PPR vaccines and companion serological tests do not enable serological differentiation between naturally infected and vaccinated animals (DIVA), therefore a meaningful serological assessment of vaccine coverage and epidemiological surveillance is not possible. Therefore, the main objective of this PhD study was to establish a reverse genetics system for PPRV, so that a marker vaccine could be developed to enable the serological differentiation between vaccination and infection, alongside developing proof of concept for increasing the valency of the existing vaccines. Initially, as a prerequisite to full genome synthesis the full genome sequence for a PPRV vaccine strain was confirmed. An efficient reverse genetics system for the PPRV Nigeria75/1 vaccine strain was established in this study and 3 recombinant PPRVs were rescued including a faithful clone of the vaccine strain (rPPRV Nigeria75/1), a clone expressing GFP as a heterologous protein (rPPRV+GFP Nigeria75/1) and a negatively marked vaccine containing mutations to the haemagglutinin (H) gene (rPPRV-C77 Nigeria75/1). All 3 rescued viruses showed similar growth characteristics in vitro when compared to the parental vaccine strain and, following in vivo assessment the H mutant provided full protection in goats upon virulent virus challenge. Although the mutations made to H abrogated in vitro binding of C77, the mutations made were not sufficient to enable DIVA in vivo. Finally proof of concept was developed for the segmentation of PPRV and expression of heterologous proteins in an effort to generate a multivalent vaccine. A recombinant two-segmented version of PPRV was successfully rescued that expressed GFP from one segment and the bluetongue virus VP2 from the other. This virus was partially characterised in vitro and demonstrates the potential for this approach in the development of multivalent vaccines for small ruminants.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:685203 |
| Date | January 2015 |
| Creators | Muniraju, Murali Bagalur |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/79088/ |
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