Fig. 1: Diagrammatic representation of the viral particles of BTV and RVFV.
From: A protective bivalent vaccine against Rift Valley fever and bluetongue
a Three concentric layers constituted by VP2 and VP5 (outer capsid), VP7 (intermediate layer), and VP3 (subcore) characterized BTV virions (~90 nm in diameter). The RNA polymerase complex, which is located inside the inner capsid, is composed by structural proteins VP1, VP4, and VP6. Five additional proteins (NS1, NS2, NS3/NS3A, NS4, and NS5) are synthesized inside the cell during the replicative cycle. VP2 and NS1 proteins of BTV are expressed by the recombinant MVAs. b Enveloped virions of RVFV (~90–110 nm in diameter) are characterized by a negative or ambisense RNA genome composed of three single-stranded segments (designated L, M, and S). These three RNA molecules are encapsidated by the nucleoprotein (N), shaping the nucleocapsid which interacts with the viral polymerase (L). Glycoproteins Gn and Gc, expressed by recombinant MVAs, elicit production of virus-neutralizing antibodies. Nonstructural proteins NSm and NSs are expressed during infection.
