Cytokine network in invertebrates: the very next phase of comparative immunology

Information on invertebrate cytokines has been growing impressively in the past five years. However, molecular characterization of newly discovered cytokines has not proportionally improved our understanding of the main reason underpinning their conservation among metazoans. One possible explanation is that cytokines have been conserved for the fundamental processes they control, but in mammals a single cytokine can hardly be considered as controller of complex reactions. In mammals, cytokines constitute a network of communication, and only this network can be considered the real controller of the effects that cytokines exert on immune or developmental functions. In all, the capability of constituting a network could represent the principal reason for cytokine evolution and conservation through diversification of metazoans