Avian cytokines--an overview.

In recent years the knowledge of avian cytokines has advanced and new data are continuously added. Nevertheless, some discontinuities persist and the correlations between molecular and functional levels are not completely clear. Most of the studies are focused on chicken, and comparative aspects with other avian groups are limited. The existence of T1 and T3 avian cytokines was assessed long ago and the recent relevant demonstration of the existence of T2 cytokines in birds is a further step in depicting a more complete view on avian immunology. The progressive knowledge of avian cytokines can hopefully help in developing new strategies in prophylaxis and therapy of avian diseases, not always completely controlled due to the emergence of more pathogenic strains.