Figure 4. Two AhR KO mouse strains differ in their response to influenza virus infection.

Mice (8-10 weeks of age) were infected with influenza virus (A/HKx31 (H3N2), 120 HAU, intranasally). A,B. Body weight (BW) change and survival were monitored daily. Open circles, wild-type C57Bl/6 mice; grey triangles, B6.129-Ahr^tm1Gonz (Δ1/Δ1) mice; and black squares, B6.129-Ahr^tm1Bra/J (Δ2/Δ2) mice. C-F. Remaining mice were sacrificed 7 days after infection. C. Bars represent the average percentage of neutrophils in the lung lavage fluid. The number of neutrophils was also significantly higher in airways of Δ1/Δ1 mice (data not shown). D,E. The mean IFNγ concentration in clarified lung lavage fluid (D), and produced by ex vivo re-stimulated mediastinal lymph node cells (E) was determined by ELISA [42, 62]. F. The number of CD8⁺ T cells in the MLN with an effector phenotype (CD44^hiCD62L^lo) was determined by flow cytometry [42]. Both AhR KO strains are on a C57Bl/6 genetic background. Error bars depict the SEM. Bars that share the same letter were not significantly different (p ≤ 0.05).