IFNB1 and infection: Primary cells (NHBEs) were found to up-regulate IFN-β secretion in response to either MV infection (which has previously been demonstrated to produce IFN-β upon infection of human fibroblasts, probably through PKR activation [24]) or following exposure to LPS (which, along with viral glycolipids, binds to and activates TLR4) (Figure 2A).