Figure 2. The inability of Ft to elicit TNF production does not reflect induction of tolerance, SOCS activity, or alternative activation of MΦ.
(A) BMDMs (5×105 cells/ml) were exposed to a low-dose primary (1°) stimulus of BHI-grown Ft LVS (MOI of 10), LPS (100 ng/ml), or BLP (100 ng/ml) for 4 h at 37°C. Cells were then washed twice and re-exposed to a higher homologous or heterologous secondary (2°) stimulus, and TNF levels were measured after 24 h. The values are expressed as mean ± sem from two independent experiments. (B and C) BMDMs (5×105 cells/ml) were infected with non-HAd (i.e., MHB-gown) or HAd (i.e., BHI- or MΦ-grown) Ft LVS (MOI of 100), and total RNA was recovered from cells after 1, 3, 6, and 24 h incubation. qPCR was used to determine transcript levels for sosc1, socs3, tnf, inos, and arg1. The values are expressed as mean ± sem from three independent experiments. *P < 0.05; ***P < 0.001.