Systemic and local immune mechanisms stimulated in the course of chicken infectious bronchitis

Abstract

Infectious bronchitis (IB) is a highly contagious, viral disease of chickens that causes damage to the respiratory tract, kidneys, gastrointestinal and reproductive systems, as well as muscles. Despite the worldwide distribution of vaccines against IB, the outbreaks of this disease are recorded frequently. This review paper describes the mechanisms of the immune system response against both infectious bronchitis virus (IBV) and vaccine IBV, with special attention to the local upper respiratory tract immune mechanisms stimulated in the course of IB. CD8+ T cells as well as IgA+ and IgY+ B memory cells seem to play the most important role in protection against re-infection with IBV. The present paper describes in detail the stimulation of non-specific innate resistance factors and the underlying mechanism of IBV innate immunity breach, as well as the stimulation and acquisition of specificity and immune memory against IBV by immunocompetent cells after both infection and vaccination.