DEC205-DC targeted DNA vaccines to CX3CR1 and CCL2 are potent and limit macrophage migration

Monocytes utilise a variety of chemokines to traffic to atherosclerotic plaques. CX3C chemokine ligand 1 (CX3CL1 & Fractalkine) and its receptor CX3CR1 and monocyte chemoattractant protein 1 (CCL2) have been identified as chemokines/receptors that have an important role in the migration and recruitment of monocytes during the pathogenesis of several inflammatory diseases including atherosclerosis. DNA vectors containing single chain variable region fragment (scFv) for DC-targeted receptor DEC205 were cloned with mouse CX3CR1 and CCL2 genes respectively, and vaccinated into C57/BL6 mice weekly for 3 weeks. Induced anti-CX3CR1 and anti-CCL2 in vaccinated mice was examined by ELISA and Western Blot analysis, while the cellular response was examined by ELISPOT. The inhibition of chemotaxis of J774 macrophages to Py-4-1 endothelial cells was examined by in vitro transwell migration assay using serum collected from vaccinated mice. All vaccinated mice generated anti-CX3CR1 and anti-CCL2 Ab and cellular response by 8 weeks after DNA vaccination. Macrophage migration towards TNF-α activated endothelial cells was significantly inhibited by serum containing both anti-CX3CR1 or anti-CCL2 Ab from vaccinated mice. These results demonstrate that DC-targeting of DNA vaccines to self-antigens generates functional immune responses which can inhibit specific key chemotactic targets. This suggests a potential therapeutic role for chemokine/receptor DNA vaccination in atherosclerosis, where chemotaxis has a pivotal role in the inflammatory process.