Poxvirus Recombinant Vaccines

Abstract

The poxvirus family, subfamily Chordopoxviridae, contains six genera. The basic criteria distinguishing membership in a genus is cross-neutralization and host-range predilection. Members of the genus Orthopoxvirus (vaccinia) and of the genus Avipoxvirus (fowlpox) have been genetically engineered to express genes from heterologous pathogens, thus providing a means of assessing these recombinant viruses as live recombinant vaccines. Vaccinia virus recombinants which have a broad host range can be useful vectors for both human and veterinary applications, while fowlpox virus recombinants, with a host range restricted to avian species, provide useful vectors for application to poultry diseases. Significantly, avipoxviruses have also been shown to be useful as vaccinating vectors in non-avian species. The results presented in this paper were selected to provide the reader with a sense of the extensive potential present in recombinant poxviruses as live recombinant vaccine candidates. The broad host range of vaccinia vectors and the narrower host range of avipoxvirus provide interesting applications. The surprising results obtained in non-avian species with recombinant fowlpox viruses are quite intriguing. The ability to generate a recombinant live vaccine that can readily be amplified in tissue culture, yet is non-proliferative in vivo, provides unique properties and interesting potential applications.