The Response of Inbred Rabbits to Vaccinia Virus Infection

Abstract

Summary The nature of the cutaneous lesion following infection with vaccinia virus has been studied, using the cutaneous lesion of bacillus Calmette-Guérin (BCG) infection for a reference. Rabbits inbred for susceptibility and resistance to tuberculosis were infected with vaccinia virus, and 1 week later with BCG. The vaccinia lesion and BCG lesions behaved similarly with respect to timing, magnitude and severity within each rabbit strain. Rabbits resistant to tuberculosis rapidly developed severe BCG and vaccinia lesions which healed readily; susceptible rabbits slowly developed smaller lesions which healed with difficulty. Delayed hypersensitivity to vaccinia virus antigens and O.T. appeared early in the resistant rabbits, late or not at all in susceptible ones. In spite of the variation in size and severity of the cutaneous vaccinia lesions among the strains of rabbits, there was no significant difference in the titer of virus recovered from the inoculation sites. The similarity in development of cutaneous lesions and delayed hypersensitivity in inbred strains of rabbits following infection with BCG and vaccinia virus was considered to support the hypothesis that delayed hypersensitivity contributes to the pathogenesis of the primary vaccinia lesion.