CCR1 blockade inhibits formation of mature OCs. (A) Representative images of monocyte cultures, grown in the presence of added RANKL and M-CSF, forming mature OCs, as shown by TRAP staining (red). Cultures were grown in the presence or absence of CCX721 (10nM). Images taken with Nikon Diaphot T20 (400× magnification). (B) Number of TRAP-positive multinucleated cells as a percentage of total cells cultured (representative results shown, experiment conducted n = 3 times). *P < .05 (Student t test).