Immune mechanisms in infections of poultry.

Resistance to infectious agents may depend upon innate mechanisms or acquired immune responses. Inflammation, phagocytosis, cell-mediated immunity and antibodies are components of a complex reaction which result either in resistance or in susceptibility. Most infectious organisms stimulate immune responses within every compartment of the immune system. In rather few infections of poultry, it is possible to pinpoint a limited number of immune reactions that are primarily responsible for resistance. In some situations, autoimmunity may contribute to the pathology associated with infections.