WHEN DID COMMUNICATION IN THE IMMUNE-SYSTEM BEGIN

Cytokines are a family of regulatory molecules that facilitate the communication between cells, most especially those of the hemopoietic system and there is evidence that the neuroendocrine system may benefit by this collaboration as well, Evolutionary evidence indicates that the beginnings of communication between cells with the protozoans as pheromone molecules. These underwent modification to become more akin to the cytokines of multicellular forms. Since the activities of invertebrate (ciliate pheromones) cytokines of multicellular forms. Since the activities of invertebrate (ciliate pheromones) cytokines are easily assayed in vertebrate systems, this suggests that the structure-function relationships of these molecules have been conserved. Cytokines have been present for millions of years in animals and as such, are important, ancient, and functionally conserved host defense molecules.