Figure 7.

Decreased survival from viral bronchopneumonia driven by overexpression of IL-12 p40 homodimer and macrophage accumulation. In A and B, wild-type (WT) and IL-12 p35 (−/−) and p40 (−/−) C57BL/6J mice were inoculated with PBS vehicle, UV-inactivated SdV, or SdV (50,000 EID₅₀), and IFN-γ, TNF-α, and IL-12 p40 levels were determined in BAL fluid obtained at day 7 after inoculation. In C, wild-type and IL-12 p35 (−/−) and p40 (−/−) mice were inoculated with SdV (50,000 EID₅₀) and differential cell counts were determined in BAL fluid obtained at day 7 after inoculation. In A–C, values represent mean ± SEM (n = 4), and a significant difference from the wild-type cohort is indicated by (*). In D, wild-type, IL-12 p35 (−/−), and IL-12 p40 (−/−) mice were inoculated with SdV (50,000 EID₅₀) and lungs at day 7 were removed and immunostained with anti-Mac3 mAb and counterstained with hematoxylin. Control nonimmune IgG gave no signal above background (not shown). Bar, 20 μm. Quantitation of macrophages per mm in length of basement membrane are provided as mean ± SEM (n = 5) for each condition.