Protein involved in innate immunity, an inborn defense mechanism used by metazoans to defend themselves against invasion by pathogens (bacteria, fungi, viruses, etc.). Initially discovered in insects which are devoid of an adaptive immune system and rely only on innate immune reactions for their defense, this immediate response accomplishes many activities including recognition and effector functions. Recognition is mediated by broad specificity, pattern recognition, receptors which recognize many related molecular structures (e.g. polysaccharides, polynucleotides) present in microorganisms but not found in the host. The innate responses include the release of antimicrobial peptides, production of cytokines, acute-phase proteins, complement.
