APCS and infection: At 4 h after inoculation, despite the slightly higher numbers of bacterial cfu in BALF and lungs of Apcs−/− mice (Table 1), the levels of TNF-α and IL-6 were lower in Apcs−/− mice than in wild-type mice (Figure 7A), suggesting that at this early stage of infection Apcs−/− mice had an impaired inflammatory cytokine response to S. pneumoniae pneumonia.