Small interfering RNA expression inhibits avian infectious bronchitis virus replication and inlammatory response

Abstract

Background: Avian infectious bronchitis virus (IBV) is a major cause of poor weight gain and mortality among chicks. Methods: A lentivirus vector was used to generate transgenic chickens expressing small interfering RNA (siRNA) targeting the M protein of IBV. Offspring of generation 0 (G0) were screened to identify G1 transgenic chickens (Tg). Monocytes from G1 Tg were stimulated with IBV in vitro. Results: Monocytes producing siRNA eficiently inhibit IBV replication. Expression of inlammatory cytokines, Mx protein and nitric oxide levels were lower in early IBV infection in Tg. In vivo experiments show that siRNA expression inhibits IBV replication, signiicantly decreases mortality and increases weight gain. Inlammatory responses and oxidative damage were signiicantly decreased, yielding minimal tissue injury. The inlammatory responses indicate that the cellular immune response is most effective during the initial stage, while the humoral immune response is more signiicant in later stages of infection. Conclusions: Small interfering RNA expression inhibits avian IBV replication and inlammatory response.