Recent studies that are focused on cnidarians as model systems for cell biology are offering key insight into the complexities of higher metazoan biology. The innate immune system of these basal invertebrates is one of the cellular processes that until recently, was undescribed. The knowledge regarding both innate immunity and other cellular processes in cnidarians is far from complete. However, the evidence acquired so far, suggests highly conserved components of these cellular processes are

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... re closely related to vertebrate homologues than more complex, but divergent invertebrate model systems. This review examines the immunorecognition and receptors that have been identified within the cnidarians so far. The complement of receptors and pathways already identified indicates that these basal invertebrates are far from "simple" in the array of methods they possess for dealing with potential invading microbes and pathogens.