Recombinant virus vaccine for bluetongue disease in sheep.

Bluetongue virus proteins derived from baculovirus expression vectors have been administered in different combinations to sheep, a vertebrate host susceptible to bluetongue virus, and the neutralizing antibody responses were measured. Vaccinated sheep were subsequently challenged, and the indices of clinical reaction were calculated. The results indicated that the outer capsid protein VP2 alone in doses of greater than 50 micrograms per sheep elicited protection. A dose of ca. 50 micrograms of VP2 protected some but not all sheep. However, when used in combination with ca. 20 micrograms of the other outer capsid protein, VP5, 50-micrograms quantities of VP2 not only protected all the vaccinated sheep but also elicited a higher neutralizing-antibody response. The addition of viral core proteins VP1, VP3, VP6, and VP7, the nonstructural proteins NS1, NS2, and NS3, and the outer capsid proteins VP2 and VP5 did not enhance this neutralizing-antibody response.