Since 1998, 9 of the 26 serotypes of bluetongue virus (BTV) have spread throughout Europe, and serotype 8 has suddenly emerged in northern Europe, causing considerable economic losses, direct (mortality and morbidity) but also indirect, due to restriction in animal movements. Therefore, many new types of vaccines, particularly subunit vaccines, with improved safety and efficacy for a broad range of BTV serotypes are currently being developed by different laboratories. Here we exploited a reverse genetics-based replication-deficient BTV serotype 1 (BTV-1) (disabled infectious single cycle [DISC]) strain to generate a series of DISC vaccine strains. Cattle and sheep were vaccinated with these viruses either singly or in cocktail form as a multivalent vaccine candidate. All vaccinated animals were seroconverted and developed neutralizing antibody responses to their respective serotypes. After challenge with the virulent strains at 21 days postvaccination, vaccinated animals showed neither any clinical reaction nor viremia. Further, there was no interference with protection with a multivalent preparation of six distinct DISC viruses. These data indicate that a very-rapid-response vaccine could be developed based on which serotypes are circulating in the population at the time of an outbreak. V accination is one of the most effective approaches for controlling infectious viral diseases known to date. Extensive knowledge of the basic biology of viruses at the molecular level coupled with recent technology developments has resulted in a number of newly designed vaccines for both human and animal viral diseases. However, the generation of effective vaccines for viruses with multiple distinct serotypes remains laborious and highly challenging. The insect-borne bluetongue virus (BTV) consists of 26 serologically distinct viral serotypes (1). BTV is the causative agent of bluetongue (BT) disease of ruminants (sheep, goats, and cattle), with sheep being the most susceptible host with the highest mortality rate. BTV is endemic in both tropical and subtropical countries of the world, and it was considered exotic in Europe prior to 1998. However, several outbreaks in Europe of a number of BTV serotypes, which caused significant losses in European livestock and agriculture, have since been reported.BTV belongs to the Orbivirus genus in the Reoviridae family, and like other members of the family, BTV is a nonenveloped icosahedral particle. BTV possesses a complex double-capsid structure consisting of seven structural proteins (VP1 to VP7) and a genome of 10 double-stranded RNA (dsRNA) segments. The outer capsid is made up of two major proteins, the larger ϳ110-kDa VP2 protein and the 60-kDa VP5 protein. VP2 is a highly variable, serotype-determining protein, and it binds to the cellular receptor. VP5 is less variable and is a membrane penetration protein. These two proteins loosely interact with each other, and both are directly attached to the surface layer of the inner capsid (termed the core), which consists of the remaining ...