Immune properties of invertebrate phenoloxidases

• Published in: Developmental and comparative immunology Vol. 122; p. 104098
• Main Authors: Cerenius, Lage, Söderhäll, Kenneth
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.09.2021; Elsevier Science Ltd
• Subjects: Animals; Arthropods; Arthropods - immunology; Bacteria - immunology; Cell Proliferation - physiology; Complement activation; Complement system; Cytokines; Enzyme Activation; Enzyme Precursors - metabolism; Fungi - immunology; Hemocytes - metabolism; Immunity, Innate - immunology; Innate immunity; Invertebrates; Melanin; Melaninization; Melanins - metabolism; Melanization; Microorganisms; Monophenol Monooxygenase - metabolism; Parasites; Pathogens; Pattern recognition; Phenoloxidase; Phylogeny; Proteolysis; Receptors, Pattern Recognition - immunology; Tyrosinase; Vertebrates; Viruses; Viruses - immunology; Phenoloxidase; Innate immunity; Melaninization; Complement system; Pattern recognition; Tyrosinase
• ISSN: 0145-305X; 1879-0089; 1879-0089
• DOI: 10.1016/j.dci.2021.104098

Melanin production from different types of phenoloxidases (POs) confers immunity from a variety of pathogens ranging from viruses and microorganisms to parasites. The arthropod proPO expresses a variety of activities including cytokine, opsonin and microbiocidal activities independent of and even without melanin production. Proteolytic processing of proPO and its activating enzyme gives rise to several peptide fragments with a variety of separate activities in a process reminiscent of vertebrate complement system activation although proPO bears no sequence similarity to vertebrate complement factors. Pathogens influence proPO activation and thereby what types of immune effects that will be produced. An increasing number of specialised pathogens – from parasites to viruses – have been identified who can synthesise compounds specifically aimed at the proPO-system. In invertebrates outside the arthropods phylogenetically unrelated POs are participating in melanization reactions obviously aimed at intruders and/or aberrant tissues. •Melanin production from different types of phenoloxidases confer immunity from a variety of pathogens.•The arthropod prophenoloxidase expresses a variety of immune activities even without melanin production.•Proteolytic processing of the arthropod prophenoloxidase system is reminiscent of vertebrate complement activation.•Phylogenetically unrelated phenoloxidases participate in immune reactions in other invertebrates.