Furthermore, at 2 wk postinfection, the number of CD4+CD25+FoxP3+ Treg cells was significantly lower in the lungs of CSE−/− mice (Fig. 3M), which was reversed at 4 wk postinfection (Fig. 3N), suggesting control of the proinflammatory immune response in the CSE−/− mice after 4 wk of infection. The gene discussed is CD4; the disease is infection.