Clodronate (Cl2MBP; dichloromethylene-biphosphonate)-loaded liposomes (CLL) were used to deplete phagocytic cells [42, 43] . Clodronate was a gift of Roche Diagnostics GmbH, (Mannheim, Germany). It was encapsulated in liposomes as described earlier [42, 43] . Mice were injected i.p. with 300 mL and i.v. with 200 mL CLL. Control mice were treated i.p. and i.v. with PBS-loaded liposomes. Twenty-four hours later, single-cell suspensions were prepared from blood and spleen. FcR blocking reagent mouse (Miltenyi Biotec, Bergisch Gladbach, Germany) was used to block non-antigen-specific binding of immunoglobulins to Fc-receptors. Cells were stained using combination of the following antibodies: FITC-conjugated rat anti-mouse CD11b (BD Pharmingen), PEconjugated rat anti-mouse CD115 (eBioscience.com), APCconjugated rat anti-mouse F4/80 (eBioscience.com), PE-conjugated hamster anti-mouse CD11c (BD Pharmingen) and Pacific Blueconjugated rat anti-mouse Ly6G/Gr-1 (eBioscience.com). All staining procedures were conducted on ice. Fluorescence data were obtained and analyzed using MACSQuant Analyzer and MACSQuantify software (Miltenyi Biotec). Challenge with 10 4 PFU rZHDNS-hRLuc was performed by injection into the ear, 24 h after liposome treatment.