Premature death and lung inflammation in lyn^−/−;PLC-β3^−/− mice. (A) Lyn phosphorylation at Tyr³⁹⁶ was measured in BM cells by immunoblotting. (B) Survival analysis of lyn^−/−;PLC-β3^−/− mice. The numbers of mice used: wt, 12; PLC-β3^−/−, 36; lyn^−/−, 16; lyn^−/−;PLC-β3^−/−, 32. (C) Immunofluorescent staining for F4/80 and Ym-1 in frozen sections of lung tissues. DAPI (4′,6-diamidino-2-phenylindole) is nuclear staining. Bar indicates 50 μm. (D) Cells in bronchoalveolar lavage fluid (BALF) were analyzed for CD11b and F4/80 expression by flow cytometry. The total cell and CD11b⁺F4/80⁻ cell numbers were calculated (n = 4-7). Data are mean ± SD, *P < .05, **P < .01.