Innate immune system antimicrobial peptides

Radek, K., Gallo, R. Antimicrobial peptides natural effectors of the innate immune system. Semin Immunopathol 29 (2007) 27—43. 

Many peptide antibiotics have been described and can be broadly classified as non-ribosomally synthesized peptides they include the polymyxins, bacitracins and gramicidins as well as the glycopep-tides (section 5) and the ribosomally synthesized peptides such as the antimicrobial peptides of the innate immune system. Polymyxins and other... 

Staphylococcus aureus causes a number of community- and hospital derived infections ranging from uncomplicated wound infections to severe diseases as septicemia or endocarditis. S. aureus expresses a large number of proteins that specifically impair the effectiveness of the innate immune system. " These include factors that modulate antimicrobial peptides and plu ocytic cells but also complement modulators (Table 1). The first anti-opsonic molecule identified in S. aureus was Staphylococcal protein A (SpA) (42 kDa), a surface protein that can also be released in the extracellular milieu. By binding the Fc part of G molecules, SpA covers the bacterial surface with G molecules in a manner that prevents recognition by Fc-receptors on phi ocytes. This way, SpA blocks Fc-receptor mediated ph ocytosis. Furthermore, since SpA interferes with C Iq binding it prevents classical pathway complement fixation as welL ... 

Pasupuleti M, Schmidtchen A, Malmsten M. Antimicrobial peptides key components of the innate immune system. CritRev Biotechnol 2012 32 143-71. 

Abstract Infectious diseases cause severe problems in the aquaculture industry, with viral diseases being responsible for the greatest losses in production. Disease prevention strategies still have some limitations in terms of safety and efficacy. Antimicrobial peptides (AMPs) are molecules of the innate immune system, one of the first lines of defense against pathogens. Usually they not only exhibit antimicrobial activity, but also modulate the immune response. This review focuses on fish AMPs and their antiviral and immunoregulatory activities in order to assess their potential relevance to aquaculture. Since fish depend on their innate immune defenses more than mammals, they could be an alternative source of novel antiviral compounds. 

Higher vertebrates have developed an innate or natural immune response, as well as an adaptive response, to fight off microbial invasions. The innate immune response is triggered immediately after microbes attack the organism. The immune system targets common structures conserved in many micro-organisms to fend them off, and antimicrobial peptides -which are produced in large quantities at sites of infection and inflammation - are ancient weapons in these defense mechanisms [24]. 

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