IL6 and infection: In addition, we found that TGF‐β levels was higher in NK cell‐depleted mice than control mice in the lung and mediastinal lymph node cells at days 6 and 12 after infection (Fig. 7C and D) while IL‐6 level was lower in NK cell‐depleted mice than control mice in both lung and mediastinal lymph node cells at days 6 and 12 (all P < 0.05, Fig. 7E and F).