Aerosol inoculation with the H6N1, H10N7, and H10N8 viruses significantly increased viral titres and upregulated the interferon (IFN)-γ, interleukin (IL)-6, and IL-1β genes in the trachea and lung tissues compared to intranasal or oral inoculation.
Results indicated that upregulation of proinflammatory cytokines (such as IL-6 and IL-1β) and lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF) expression is induced by IBV M41 in the trachea and by IBV 885 and QX in the kidney, which mainly coincides with tracheal and renal histopathological lesions respectively caused by these strains.