The effect of IRAK-2 knockdown in macrophages is allele specific. (A and B) BMDMs from C57BL/6J and C57BL/6J-Why1^MOLF/MOLF mice were transduced with control or an IRAK-2–targeting shRNA construct. Cells were stimulated with 2 µg/ml LTA for 6 h followed by IL-6 ELISA analysis (A) or for the indicated times followed by IL-6 mRNA quantification by real-time PCR (B). Real-time PCR data are shown as the fold change (in Ct values) observed in IRAK-2 shRNA treated relative to control-treated cells. Data shown as mean ± SEM from triplicate wells (A) or ± range from duplicate wells (B), representative of two independent experiments. (C) Peritoneal macrophages from 14 Why1 homozygous or 9 heterozygous N2 backcross mice were plated and infected with control or IRAK-2–targeting shRNA constructs. 3 d after infection, cells were stimulated with 2 µg/ml LTA and IL-6 protein secretion was measured by ELISA. Mean values of three wells for each mouse are plotted. P-values were calculated using a paired Student's t test analysis.