Figure 6
Localization of CCL2 and CXCL10 mRNA in lung tissue explants non-cultured and cultured with IL-1β and IFN-γ, in the presence or absence of 10-4 M dexamethasone (DEX) for 24 h. CCL2 mRNA is constitutively produced in normal lung tissue by AEC-II (arrowheads) and AM (arrows) (A ), and stimulation with 500 U/ml of human recombinant IL-1β and IFN-γ (C , inset) significantly up-regulates CCL2 mRNA expression by these cells compared to non-cultured (A ) or 24-h cultured controls (data not shown). AEC-I also show weak positive signal for CCL2 mRNA (C , sharp arrowheads). DEX treatment leads to inhibition of the IL-1β-induced CCL2 mRNA production in AEC-II (E and C ), but does not change the basal expression (E and A ). Panels B , D , and F show the same lung tissue explants treated as indicated above and hybridized with a CXCL10 specific probe. Panel D (inset) illustrates a prominent inducible effect of cytokine-stimulation on CXCL10 mRNA expression in situ by AEC-II (arrowheads) and AM (arrows), and panel F depicts the inhibitory effect of DEX on IFN-γ/IL-1β-induced CXCL10 mRNA expression. Data of one representative experiment from five are shown. Panels G and H illustrate CXCL10 mRNA localization in the lung from patients with pulmonary sarcoidosis and tuberculosis respectively. Control slides, in which hybridization buffer alone was applied, display no reactivity in all experiments (data not shown).