Modulation of the avian immune system: suppression versus induction of immunity.

: Knowledge of the potential, but also of the vulnerability of the avian immune system is not only of academic interest. The intact immune system, beginning in the embryo, is of central significance to safeguarding health and productivity in poultry flocks. Interactions between cellular and soluble constituents of the avian immune system on one hand, and the nature of immunosuppressants on the other, determine whether the avian immune system is able to cope with microbial and non-microbial challenges. Modulation of the immune response can be achieved in the classical way by specific vaccinations or possibly in the future by DNA vaccination. Cytokine inducing compounds may provide additional tools to enhance immune reactivity. The future will tell whether these approaches will be applicable in disease preventation or treatment in poultry medicine. In concert with these tools, however, strict hygiene measures from incubation until production, slaughter and processing are equally of vital significance as part of disease prevention strategies, ultimately leading to high quality food products originating from animal production.