Figure 2
Mycobacterial infection delays T helper type 1 (Th1) cell responses and suppresses proinflammatory responses via DAP12 (DNAX-activating protein of 12 kDa) pathway. Lung cells were isolated and stimulated at days 5 (d5), 7 (d7), and 14 (d14) after infection with Mycobacterium tuberculosis (M. tb) from wild-type (WT) and DAP12 knockout (KO) mice and subject to immunostaining. Representative dot plots showing frequencies and absolute numbers of CD4+ interferon-γ-positive (IFN-γ+) cells in the lung at (a) d5, (b) d7, and (c) d14 are presented. Sti, stimulated; Unsti, unstimulated. (d) Experimental schema of reconstitution of DAP12 using AdDAP12 in DAP12 KO mice. (e) Lung cells isolated 14 days after infection from DAP12 KO mice receiving either Addl or AdDAP12 were subject to immunostaining. Representative dot plots depict frequencies of CD4+ IFN-γ+ cells in the lung. The data are expressed as mean±s.e.m. of cell numbers from three to four mice per group, representative of more than two independent experiments. Lung homogenates from WT and DAP12 KO mice at d7 or d14 or d21 after infection were measured for (f) tumor necrosis factor-α (TNF-α) and (g) interleukin-10 (IL-10) by enzyme-linked immunosorbent assay (ELISA). Results are expressed as mean±s.e.m. of cytokine levels from three mice per group, representative of two independent experiments. *P<0.05, **P<0.01.
