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Gene expression profiling failed to identify candidate ‘endothelial protective’ mediators and attention focussed on elafin and secretory leucocyte protease inhibitor (SLPI), two low molecular weight elastase inhibitors. Elafin has been demonstrated within human coronary arteries although its function as a locally active antiprotease, antagonising the inflammatory effects of human neurophil elastase (HNE) and bacterial injury has best been characterised within the lung. Here we have used adenovirus as a vector to deliver elafin and SLPI genes to human endothelial cells and macrophages. We have devised a protocol involving pre-complexing of adenovirus with lipofectamine to enhance gene delivery and subsequent gene expression in human endothelial cells and to facilitate gene delivery to human macrophages. Elafin and SLPI overexpression were associated with reduced inflammatory cytokine production in endothelial cells and macrophages in response to a range of atherogenic stimuli including oxidised LDL. This anti-inflammatory activity was associated with reduced activation of the transcription factor NF-κB and preservation of its inhibitory sub-unit IκBα. Furthermore, elafin overexpression protected endothelial cells from HNE mediated injury and attenuated HNE mediated impairment of macrophage apoptotic cell recognition. In summary, angiopoietin-2 was identified as a novel mediator produced by endothelial cells in response to oxidised LDL and may contribute to plaque development through facilitation of neointimal angiogenesis. Adenoviral overexpression of elafin and SLPI exhibited therapeutic potential through reducing inflammatory responses and protecting the structure and function of endothelial cells and macrophages in the presence of atherogenic stimuli.