Novel roles of osteopontin and CXC chemokine ligand 7 in the defence against mycobacterial infection.

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced human monocyte-derived macrophage (GM-Mφ) or macrophage CSF (M-CSF)-induced human monocyte-derived Mφ (M-Mφ) are distinct in terms of the resistance to Mycobacterium tuberculosis. To elucidate the role of molecules involved in the functional differences between these Mφs, we investigated the gene expression profiles using microarray. After culture of CD14⁺ monocytes with CSFs, Mφs were cultured with or without bacillus Calmette–Guérin (BCG) (GM-Mφ-BCG and M-Mφ-BCG). The gene expression profiles from these cells were compared. Chemokines highly expressed in M-Mφs were selected and evaluated for anti-mycobacterial activity and superoxide production. FN1 and FCGR2B were the most up-regulated genes in GM-Mφ and M-Mφ, respectively. After stimulation with BCG, three chemokine genes ( Osteopontin ( SPP1), CXC chemokine ligand 7 ( CXCL7) and CC chemokine ligand 11 ( CCL11)) were highly expressed in M-Mφ-BCG when compared to those in GM-Mφ-BCG. A significantly increased resistance to M. tuberculosis H37Ra was observed after the stimulation of GM-Mφ with SPP1 or CXCL7. Superoxide production levels of SPP1- or CXCL7-stimulated GM-Mφs were higher than those of GM-Mφs without stimulation. These results indicate that both SPP1 and CXCL7 might have a role in the resistance against mycobacteria, at least in part, through augmenting reactive oxygen intermediate production in Mφs. [ABSTRACT FROM AUTHOR]