Schematic of hBD3 and Lipofectamine 2000 interaction with HMW polyI:C.

Pale arrows indicate relative amounts of HMW polyI:C accessing different areas of the cell under our three different treatment conditions. The cell membrane is indicated by a double line, MAVS is located adjacent to the mitochondria. MDA5 is free in cytoplasm but goes to MAVS adaptor to generate the signalling cascade that results in IRF activation and production of Interferon-β (IFNβ). The black arrows indicate the strength of signalling that results in IFNβ or CXCL10 production with the dotted line indicating least signalling and the widest line indicating most signalling. Compared to polyI:C alone, hBD3 increases IFNβ production from MDA5 signalling and despite reducing the amount from TLR3, overall IFNβ levels rise. CXCL10 production from TLR3 is reduced by polyI:C in the presence of hBD3 because less is located at the endosome available for TLR3 signalling. In the presence of Lipofectamine, polyI:C production by TLR3/TICAM1 of CXCL10 increases due to increased endosomal signalling.