Fig. 1.

Osteoclasts produce T cell-active chemokines capable of inducing γδ T cell chemotaxis. A.) Conditioned medium was harvested from 48 h cultures of macrophages (MΦ) or mature osteoclasts (OC) and cytokine/chemokine profiles were determined using a Proteome Profiler Human Cytokine Array Kit (R&D Systems), according to the manufacturer's instructions. Proteins of interest are highlighted (GROα = CXCL1; IL-8 = CXCL8; MCP-1 = CCL2). Data shown are representative of two independent experiments using conditioned medium from macrophages and osteoclasts derived from two different donors. B.) A Transwell chemotaxis assay was conducted using serum-free medium, medium containing 10% FBS, or serum-free osteoclast conditioned medium (OC CM) as chemoattractants. Purified γδ T cells (pre-activated with 100 U/ml IL-2 for 12 h) were added into the Transwell inserts (8 μm pore size) and the cells were incubated for 4 h at 37 °C. Migrated cells were harvested and quantified using flow cytometric analysis. Migration of γδ T cells is normalised to fold-change of FBS-stimulated migration. Data shown are mean + S.E.M. using γδ T cells from four independent donors.