Fig 1: Osteoclast formation assay. A, TRAP assay on supernatants from SFMC osteoclast cultures after 21 days of stimulation with RANKL and M-CSF (NT) and indicated treatments. Formation presented as ratio, calculated: Treatment / NT. Cells treated with rhPD-L1 demonstrated a tendency towards decreased levels of TRAP activity. rhGal-3 significantly increased TRAP activity .rhPD-L1 and rhGal-3 in combination significantly increased TRAP activity compared to rhPD-L1 treatment only. RA SFMCs (n = 3). b) Image of osteoclasts generated from RA SFMCs. Black arrows marking examples of osteoclasts, identified as pink TRAP positive, multinucleated cells.