The CLEC-2/PDPN interaction induces BM FRC-like cells to secrete a PPF-facilitating factor, CCL5. Identification of PPF-facilitating factor in CLEC-2–conditioned medium (supernatant from CLEC-2–stimulated BM FRC-like cells). (A) Results obtained using the Proteome Profiler Mouse Cytokine Array Panel A. The top and bottom panels indicate the acquired array images from rFC2-conditioned medium and CLEC-2–rFC2-conditioned medium, respectively. (B) Spot intensity on the Proteome Profiler Mouse Cytokine Array Panel A with rFC2- and CLEC-2–rFC2-conditioned medium. This graph shows quantitative results of the images shown in panel A. Values above each bar indicate the fold-change of rFC2-conditioned medium (blue bar) relative to CLEC-2–conditioned medium (red bar). (C) PPF assay with recombinant CXCL10, CXCL2, and CCL5 (n = 6 per group). (D) CCL5-neutralizing antibody (AF478, 1.5 μg/mL final) suppressed PPF in culture with CLEC-2–conditioned medium (n = 6 per group). The error bars represent SEMs. *P < .05, **P < .01. Cont Ig, control immunoglobulin; IL-1ra, IL-1 receptor antagonist; NC, negative control; TNF-a, tumor necrosis factor-α.