Recombinant vaccinia virus expressing the PR/8 influenza hemagglutinin gene overcomes the impaired immune response and increased susceptibility of old mice to influenza infection.
Academic Article
Overview
abstract
Elderly humans have increased morbidity and mortality after viral influenza despite immunization. A mouse model of influenza infection was used to search for a more effective way to induce immunity to influenza. Old (18 months) BALB/c mice were more susceptible to influenza pneumonia than young (2 months) BALB/c mice after intranasal challenge with PR/8 influenza virus despite prior immunization with influenza virus. The decreased resistance to live influenza virus challenge was associated with an impaired generation of anti-hemagglutinin antibody and cytotoxic T lymphocytes in old mice. In contrast, immunization of old mice with a recombinant vaccinia virus expressing the PR/8 influenza hemagglutinin gene protected them from intranasal challenge with live influenza virus and generated high levels of anti-PR/8 influenza virus hemagglutinin antibody and PR/8-specific cytotoxic T cells. Recombinant vaccine overcame the age-associated immune defect that follows the administration of conventional viral vaccine.