Inflammatory damage following first-generation replication-defective adenovirus controlled by anti-LFA-1

First-generation replication-defective adenoviruses have been reported to lead to transient reporter gene expression due to a specific immune reaction involving T and B lymphocytes. Some recent reports have also demonstrated the presence of a nonspecific inflammatory reaction involving macrophages and neutrophils after both intramuscular injections and viral vectors transduction. To further investigate this nonspecific inflammatory reaction, deltaE1/E3a adenoviruses were injected intramuscularly in immunocompetent mice. Some of these mice were treated with anti-LFA-1. The adenovirus-injected muscles showed abundant CD4+, CD8+, LFA-1+, and Mac-1+ cell infiltration 3 days after the deltaE1/E3a injection. The anti-LFA-1 monoclonal antibody was able to block the nonspecific inflammatory damage due mostly to neutrophils and macrophages. The anti-LFA-1 did not produce this effect by reducing the muscle infiltration by LFA-1+ cells. It may instead have blocked the direct interaction between LFA-1 and ICAM-1 thus preventing the damage produced by the respiratory burst of neutrophils. Blocking the resulting damage of this inflammatory reaction with anti-LFA-1 in animals also treated with FK506, a powerful immunosuppressant for gene therapy, largely increased the long-term transgene expression compared with mice only treated with FK506.