Figure 3.

Neutralization of tumor necrosis factor α (TNF-α) enhances regulatory T-cell (Treg) proliferation in wild-type (WT) and CCR5^–/– lungs. WT and CCR5^–/– mice were given a monoclonal antibody to TNF-α or rat immunoglobulin G (IgG) and intranasally infected with 2 × 10⁶ yeasts. Mice were intraperitoneally given bromodeoxyuridine (BrdU) for 2 consecutive days before being killed. At day 7 postinfection, the percentage of Tregs (CD4⁺ Foxp3⁺ T cells) that incorporated BrdU was measured by flow cytometry (A). RNA was extracted from lung leukocytes at day 7 postinfection and interleukin 2 (IL-2) expression was measured by quantitative real-time polymerase chain reaction. Hypoxanthine-guanine phosphoribosyltransferase was used as an endogenous control, and values represent log increase compared with respective IgG controls (B). Data represent the mean ± SEM (n = 6–12) from 2–3 experiments. **P < .01; ***P < .001.