A Broad-Spectrum Chemokine-Binding Protein of Bovine Papular Stomatitis Virus Inhibits Neutrophil and Monocyte Infiltration in Inflammatory and Wound Models of Mouse Skin

Abstract

Bovine papular stomatitis virus (BPSV) is a Parapoxvirus that induces acute pustular skin lesions in cattle and is transmissible to humans. Previous studies have shown that BPSV encodes a distinctive chemokine-binding protein (CBP). Chemokines are critically involved in the trafficking of immune cells to sites of inflammation and infected tissue, suggesting that the CBP plays a role in immune evasion by preventing immune cells reaching sites of infection. We hypothesised that the BPSV-CBP binds a wide range of inflammatory chemokines particularly those involved in BPSV skin infection, and inhibits the recruitment of immune cells from the blood into inflamed skin. Molecular analysis of the purified protein revealed that the BPSV-CBP is a homodimeric polypeptide with a MW of 82.4 kDa whilst a comprehensive screen of inflammatory chemokines by surface plasmon resonance showed high-affinity binding to a range of chemokines within the CXC, CC and XC subfamilies. Structural analysis of BPSV-CBP, based on the crystal structure of orf virus CBP, provided a probable explanation for these chemokine specificities at a molecular level. Functional analysis of the BPSV-CBP using transwell migration assays demonstrated that it potently inhibited chemotaxis of murine neutrophils and monocytes in response to CXCL1, CXCL2 as well as CCL2, CCL3 and CCL5 chemokines. In order to examine the effects of CBP in vivo, we used murine skin models to determine its impact on inflammatory cell recruitment such as that observed during BPSV infection. Intradermal injection of BPSV-CBP blocked the influx of neutrophils and monocytes in murine skin in which inflammation was induced with lipopolysaccharide. Furthermore, intradermal injection of BPSV-CBP into injured skin, which more closely mimics BPSV lesions, delayed the influx of neutrophils and reduced the recruitment of MHC-II+ immune cells to the wound bed. Our findings suggest that the CBP could be important in pathogenesis of BPSV infections.

Deriving Immune Modulating Drugs from Viruses—A New Class of Biologics

“…The 35K proteins have been tested and have shown some benefit in atherosclerosis and arthritis models [97,98]. Treatment with M-T1 proved beneficial in reducing pathology in rodent models of angioplasty injury and aortic allograft inflammation [99].…”

“…Not surprisingly, the deletion of this immune-modulator from the ORFV genome severely attenuates infection of sheep, reducing pustule formation and increasing dermal monocyte and dendritic cell recruitment to the lesion, relative to the wildtype virus [128]. The ORFV CBP is conserved across parapoxviruses, but with low identity across species [99,[129][130][131][132].…”

“…The CBP encoded by BPSV shows the greatest similarity to that of ORFV, with the recombinant protein binding strongly to chemokines within the CXC, CC and C subfamilies, and inhibiting neutrophil and monocyte recruitment in vitro and a murine model of skin inflammation [99]. Intriguingly, three variants have been identified in the genome of Parapoxvirus of red deer of New Zealand (PVNZ) [132], and these CBPs exhibit differences in binding specificity.…”

“…The broad spectrum of activity of the parapoxvirus CBPs has led to investigations as to their therapeutic utility in preclinical models of acute inflammation. Intradermal injection of the BPSV CBP into injured murine skin delayed the influx of neutrophils and reduced the accumulation of MHC-II+ immune cells within the wound bed [99]. Treatment with the BPSV CBP also suppressed inflammation post cerebrovascular accident (stroke) in mice [101].…”

Engineered anti-inflammatory peptides inspired by mapping an evasin–chemokine interaction

“…This phenomenon suggests that the ability to target multiple chemokines is an effective strategy to disable the chemokine network and host defense mechanisms such as inflammation. The application of such chemokine-binding proteins in diverse preclinical models of inflammation has been well-documented (15,16). Of particular interest in the development of therapeutics that target chemokines are the evasin proteins from ticks.…”