Mechanisms for a Novel Immune Evasion Strategy in the Scabies Mite Sarcoptes Scabiei: A Multigene Family of Inactivated Serine Proteases

• Published in: Journal of investigative dermatology Vol. 121; no. 6; pp. 1419 - 1424
• Main Authors: Wilson, Peter, Slade, Robert, Currie, Bart J., Walton, Shelley F., Holt, Deborah C., Fischer, Katja, Allen, George E., Wilson, Danny, Kemp, David J.
• Format: Journal Article
• Language: English
• Published: Danvers, MA Elsevier Inc 01-12-2003; Nature Publishing; Elsevier Limited
• Subjects: Allergens - genetics; Amino Acid Sequence; Animals; Biological and medical sciences; Gene Library; group 3 allergens; Human parasitic diseases due to arthropods; Infectious diseases; Medical sciences; Molecular Sequence Data; Multigene Family - genetics; Multigene Family - immunology; Parasitic diseases; Phylogeny; protease activated receptors; Pyroglyphidae - genetics; Pyroglyphidae - immunology; Sarcoptes scabiei - genetics; Sarcoptes scabiei - immunology; Sarcoptes scabiei - pathogenicity; Serine Endopeptidases - genetics; Serine Endopeptidases - immunology; Virulence; protease activated receptors; group 3 allergens; Skin disease; Sarcoptes scabiei; Serine endopeptidases; Enzyme; Dermatology; Acaridida; Mite; Parasitosis; Mechanism; Infection; Peptidases; Acariformes; Arachnida; Acari; group 3 allergens/protease activated receptors; Arthropoda; Hydrolases; Multigene family; Protease-activated receptor; Invertebrata; Scabies; Sarcoptidae; Allergen
• ISSN: 0022-202X; 1523-1747
• DOI: 10.1046/j.1523-1747.2003.12621.x

Parasitic infestation of the skin by the mite Sarcoptes scabiei is a significant problem worldwide, particularly in socially disadvantaged communities. A multigene family of at least 24 homologs of a serine protease allergen have been identified in S. scabiei. Surprisingly, the products of all but one of these genes are predicted to be catalytically inactive, due to mutations at a critical triad of amino acids at the active site. We discuss the possibility that these genes for inactivated proteases have been conserved because they mediate a novel host defense evasion strategy that the mite has evolved as an adaptation to parasitism of the epidermis. The identification of this family, and elucidation of its value to the parasite, may present an unanticipated approach to protective vaccination.