Avian Immune System: an Overview

In common with other animals birds have evolved an immune system that is capable of responding to and protecting against pathogens such as Escherichia coli Salmonella sp. Pasteurella multocida coronavirus and avian Influenza A virus . The immune system is generally divided into two main branches: the adaptive (specific) and the innate (non-specific) immune responses. Components of the immune system (i.e. adaptive and innate) include T-lymphocytes B-lymphocytes macrophages natural killer (NK) cells heterophils basophils diverse humoral communication factors such as eicosanoids and cytokines (e.g. interleukins interferons tumor necrosis factor) and effector molecules (e.g. immunoglobulins complement lysozymes nitric oxide). Additionally some tissues in the body are dedicated to support the immune system such as dendritic reticular and stromal cells. Regulation interaction and communication between various elements of the specific and the innate immune responses result into birds possessing a highly sophisticated immune system capable of protecting against invading pathogens.