Immune Response: Evolution

Abstract

Innate immune processes arose from specific host–pathogen coevolutive interactions and the ability to recognise self and nonself structures is extremely conserved from invertebrates to vertebrates. In this context, phagocytes represent the most ancient defensive line against foreign materials, already present in earliest protostomes. Moreover, although more complex functions evolved in vertebrates, both cellular and humoral innate immune mechanisms are extremely conserved, leading to identify some forms of innate immune memory also in invertebrates. Key Concepts Phagocytosis represents the first mechanism of defence in metazoans. Immune system has evolved to discriminate self and nonself structures. Immune mechanisms present a high level of conservation throughout phyla . Vertebrate innate immune memory derives from ancient forms and mechanisms already present in invertebrates. Alternative animal models are crucial for investigating the molecular basis of the immune processes.