Distinct chemokine and cytokine gene expression pattern of murine dendritic cells and macrophages in response to Mycobacterium tuberculosis infection

In this study, the early innate cytokine and chemokine response of murine dendritic cells (DCs) and macrophages to Mycobacterium tuberculosis infection was compared. The findings indicate a dissimilar gene expression pattern between the two cell types. The expression of IL-12 and IL-23, important for promoting Th1 and Th17 cells, respectively, was up-regulated only in DCs. In addition, expression of CCL1 and CCL17, which are important in recruitment of T regulatory cells, was DC-specific, as was the expression of the immunosuppressive cytokine IL-10. Macrophages, in contrast, exhibited enhanced expression for CCL2 and CXCL10, chemokines that recruit cells to sites of inflammation, and for mycobactericidal molecules NO synthase 2 and TNF. Together, the findings suggest that a component of the innate DC response is not only programmed toward Th1 priming but is also for controlling the magnitude of the Th1 response, and part of the macrophage response is intended for recruiting cells to the lung and for mycobactericidal functions.