NK-like cells are responsible for enhanced MCMV-specific CD4 T cell response in <i>Il10</i>^−/− mice.

<p>B6 and <i>Il10</i>^−/− mice were infected with 5×10⁶ PFU <i>Δm157</i> MCMV. A–D) B6 and <i>Il10</i>^−/− mice were either mock treated or depleted of NK-like cells using αNK1.1 (PK136) antibody. A) Lymphocytes from lungs were isolated at day 5.5. p.i. and <i>ex vivo</i> restimulated with a pool of M14, m18, M25, M112, m139 and m142 peptides (CD4 peptide pool). Percentages of IFN-γ⁺TNF-α⁺ peptide specific CD4 cells are shown (n = 3, error bars indicate standard deviation, data are representative from at least 3 experiments). B) Virus titers were determined in salivary glands at day 14 p.i. Each symbol represents one individual mouse, horizontal line indicates the mean, dashed line indicates detection limit (n = 3, data are representative of 2 independent experiments). C) IFN-γ, TNF-α and IL-12 protein concentrations were determined in the sera of B6 and <i>Il10</i>^−/− mice at day 3.5 p.i. Each symbol represents one individual mouse, horizontal line indicates the mean (n = 3, data are representative of 2 independent experiments). D) Body weight change of B6 and <i>Il10</i>^−/− mice was measured at the indicated time points. Changes in percentage of body weight relative to day 0 are shown. Each symbol represents the mean of 3 mice per group; vertical bars indicate the standard deviation. Data are representative of 3 independent experiments. E) Splenic NK1.1⁺CD3ε⁻ NK cells (NK) were isolated from B6 and <i>Il10</i>^−/− mice at day 3.5 p.i. Total numbers of IFN-γ⁺ NK cells and MFI of IFN-γ⁺ in NK cells are shown (upper panel). Total numbers of TNF-α⁺ NK cells and expression levels of NKG2D and NCR-1 on NK cells are shown (lower panel). Error bars indicate standard deviation; n = 3, data are representative of 3 independent experiments. Statistical analysis was performed by 2-tailed unpaired student's t-test (* p<0.05, ** p<0.01, *** p<0.001).