A soft tick Ornithodoros moubata salivary protein OmCI is a potent inhibitor to prevent avian complement activation

Publication date: Available online 6 December 2019Source: Ticks and Tick-borne DiseasesAuthor(s): Amber M. Frye, Thomas M. Hart, Danielle M. Tufts, Sanjay Ram, Maria A. Diuk-Wasser, Peter Kraiczy, Anna M. Blom, Yi-Pin LinAbstractComplement is a key first line innate host defense system in the blood of vertebrates. Upon activation, this powerful defense mechanism can elicit inflammatory responses, lyse non-self-cells, or mark them for opsonophagocytic removal. Blood-feeding arthropods thus require the ability to block host complement activation in the bloodmeal to prevent undesired cell or tissue damage during feeding. The soft tick Ornithodoros moubata produces a complement inhibitory protein, OmCI. This protein binds to a mammalian complement protein C5 and blocks further activation of complement cascades, which results in the prevention of complement-mediated bacterial killing through membrane attack complex. Interestingly, the amino acids involved in OmCI binding are highly conserved among mammalian and avian C5, but the ability of this protein to inhibit the complement from birds remains unclear. Here we demonstrated that OmCI is capable of preventing quail complement-mediated erythrocyte lysis, inhibiting the capability of this animal’s complement to eliminate a serum-sensitive Lyme disease bacterial strain. We also found that the ability of OmCI to inhibit quail complement-mediated killing of Lyme disease bacteria can be extended to different domestic and wild birds. ...
Source: Ticks and Tick borne Diseases - Category: Zoology Source Type: research