Structural and functional studies on African horse sickness virus (AFHV) to engineer a protein-based vaccine prototype

African horse sickness virus (AHSV) is caused a double stranded RNA virus belonging to the genus Orbivirus, family Reoviridae, which includes bluetongue virus (BTV). As for BTV, AHSV is spread by Culicoides (midge) vectors, which feed on zebras, mules, donkeys and horses, but lead to severe effects and high mortality only in horses. Viral infection manifests as acute pulmonary and cardiac forms associated, which both have a high fatality rate (60-90%). There is no effective therapy available, the live-attenuated vaccine (LAV) used in Africa can sometimes cause disease, and the existence of nine different serotypes complicates the use of inactivated virus vaccines. Neither LAV nor inactivated virus vaccines allow the use of diagnostic tests for antibodies that can differentiate infected from vaccinated animals, which hinders control measures.
Further research is therefore required to develop a novel AFH vaccine.
PhD objectives:
Objective 1: Determine the effects of anti-VP2 and anti-VP7 mAbs and nanobodies
Objective 2: Determine the crystal structures of VP2 and VP7 in complex with mAbs/nanobodies
Objective 3: Engineering a broad-spectrum AFHV vaccine prototype
The student will design immunogens of fragments of VP2 and VP7 based on sequence analysis to broaden the sequence coverage across serotypes and to test their thermostability, as required for delivery in hot countries. These immunogens will be cloned, expressed, purified, and conjugated to virus-like particles to test their ability to boost broadly neutralizing mAbs, which will be tested as therapeutic tools to block AHSV invasion, therefore paving the way for a synthetic broad-spectrum vaccine prototype.
The success of the individual objectives is independent from the success of the other objectives but the collective information has a synergic impact on the overarching aim of the PhD project.