Adenoviral-mediated delivery of a viral chemokine binding protein blocks CC-chemokine activity in vitro and in vivo

Chemokines are important mediators of leukocyte recruitment and activation that play critical roles in the pathology of inflammatory diseases such as atherosclerosis, rheumatoid arthritis and asthma. The vaccinia virus (strain Lister) expresses a 35 kDa soluble protein ('35K') that binds and inactivates a wide range of CC chemokines. We generated a recombinant adenovirus encoding soluble 35K (Ad35K). Ad35K-infected cell culture medium, containing recombinant 35K, potently reduced migration of CCR5-transfected 293 cells by 95% in response to the CC-chemokine RANTES, but had no effect on cells transfected with the CX(3)CR1 fractalkine receptor. Delivery of Ad35K to mice in vivo via tail vein injection resulted in expression of recombinant 35K in plasma and increased serum RANTES and MIP-1alpha levels when quantified by ELISA. However, chemotaxis of both CCR5-transfected cells and primary macrophages was inhibited by more than 90% by plasma from Ad35K-infected animals compared with control plasma from animals injected with AdGFP. Furthermore, 35K delivered by intra-peritoneal injection more than halved biogel-induced inflammatory cell recruitment in peritoneal exudates compared to AdGFP medium. These studies identify broad-spectrum CC-chemokine blockade using in vivo adenoviral-mediated recombinant 35K expression as a promising strategy to reduce local and systemic inflammation.