BALB/c mice were bred and maintained in the animal facility at the University of Liverpool. C57Bl/6 mice were purchased from Banting and Kingman Universal Ltd (North Humberside, UK) and maintained in the animal facility at the University of Liverpool. 129Ev mice and type 1 IFN receptor
(IFNAR)-deficient mice on the 129 background were originally purchased from Banting and Kingman Universal Ltd and bred and maintained in the specific pathogen-free unit at the Institute for Animal Health (Compton, UK). Bone marrow was supplied by Dr P. Borrow. MyD88−/− mice on a C57Bl/6 background, TRIF−/− this website mice and their TRIF+/+ littermates were made available by Prof. R. K. Grencis (Faculty of Life Sciences, University of Manchester) with the generous permission of Prof. S. Akira (Department of Host Defense, Osaka University). All mice were used at > 8 weeks of age. All animal studies were carried out in accordance with local and UK Home Office regulations for animal care and use. RPMI-1640 medium (Sigma, Gillingham, UK) supplemented
with 2 mm l-glutamine, 100 U/ml of penicillin, 100 U/ml of streptomycin, 5 × 10−5 m 2-mercaptoethanol and 5% (v/v) fetal calf serum AZD2014 (Biosera, Ringmer, UK) was used throughout these experiments. Medium from P3-X63 cells transfected with the murine GM-CSF vector was used as a source of GM-CSF. The Leukocyte receptor tyrosine kinase medium was titrated for potency to induce DC generation from murine bone marrow. The cells were originally made by Dr Brigitta Stockinger (Division of Molecular Immunology, National Institute for Medical Research) and were a gift from Prof. David Gray (Institute of Immunology and Infection, The University of Edinburgh). LPS from Escherichia coli, Poly I and Poly I:C were purchased from Sigma, and cytosine–phosphate–guanosine (CpG) oligodeoxynucleotide (ODN) 1826 was purchased from MWG (London, UK). Influenza viruses Jap (A/Jap/1/57), PR8 (A/Puerto Rico/8/34) and the recombinant
virus X31 (A/Aichi/2/68 × A/Puerto Rico/8/34), grown in the allantoic cavity of hen eggs, were a gift from Dr B. Thomas (Sir William Dunn School of Pathology, University of Oxford). Viruses were inactivated by exposure for 3-min to ultraviolet (UV) light from a 60 W source at a distance of 20 cm and treated with polymyxin-B (Sigma) to eliminate possible contamination with LPS. CpG ODN, LPS, Jap, X31 and PR8 were used at 1 μg/ml in all experiments; Poly I and Poly I:C were used at 25 μg/ml. These doses were selected as they have been shown to be effective at eliciting an innate immune response in vitro. Recombinant TNF-α was purchased from Hycult Biotechnology (Eindhoven, Netherlands) and neutralizing antibody to TNF-α was purchased from Sigma. Recombinant TNF-α was used at a concentration of 5 ng/ml.