Development of heat-stable recombinant rinderpest vaccine.

Recombinant vaccinia virus (RVV) containing the full-length cDNA of rinderpest virus (RV)-haemagglutinin (H) gene was constructed. The H gene was inserted into the attenuated vaccine strain of vaccinia virus (VV), Le 16 m0, with two different promoters, namely cowpox virus A-type inclusion body (ATI) promoter or VV 7.5 kilodalton (P7.5) promoter. These RVVs produced the same sized fully glycosylated RV-H protein in RK 13 cells as that of the authentic RV-H. Their heat stability in the lyophylized state was similar to that of the parental VV. All rabbits immunized with these RVVs produced virus neutralizing (VN) antibody to RV as well as anti RV-H antibody. Four weeks after immunization, these animals were challenged with RV intravenously. None of the RVV-immunized rabbits developed any clinical signs of RV infection except one which was immunized with RVV containing the ATI promoter and developed low VN titer. These results indicate the possibility of developing a heat-stable recombinant vaccine for the eradication of rinderpest in tropical countries without cold storage systems.