Cytokine measurements. IFN-␥ and IL-12p70 were measured in the peritoneal lavage fluid or the serum using the mouse inflammation kit cytometric bead assay (BD Biosciences). The limits of detection were 2.5 pg/ml for IFN-␥ and 10.7 pg/ml for IL-12p70. IFN-␣ and IFN-␤ were measured in the peritoneal lavage fluid or the serum using the VeriKine mouse IFN-␣ or mouse IFN-␤ ELISA kits, respectively (PBL Interferon-Source, Piscataway, NJ). The limits of detection for these assays were 12.5 pg/ml for IFN-␣ and 15.6 pg/ml for IFN-␤. The IL-12p40 ELISA, with a limit of detection of 100 pg/ml, was done as previously described (8) .