A. RA PBMCs cultured in suboptimal conditions (10 ng/ml M-CSF and RANKL) were untreated or pretreated with 10 µg/ml of IgG, anti-TNF-α and anti-TLR5 antibodies prior to being stimulated with 10 ng/ml flagellin, followed by TRAP staining. B. Is a representative image of TRAP+ cells (original magnification x 200) from A, n=3. C. RA PBMC were cultured in suboptimal condition and were either untreated or treated with 1ng/ml flagellin, 1ng/ml TNF-α or both prior to TRAP staining. D. Is a representative image of TRAP staining (original magnification x 200) from C, n=3. E. RA PBMCs cultured in suboptimal condition were immunoneutralized by 10 µg/ml IgG control or anti-TLR5 antibodies and cells were then incubated with 2% RA SF plus IgG or 2% RA SF plus anti-TNF-α (10 µg/ml) subsequent to TRAP staining, n=4. Negative and positive control consisted of untreated cells or cells treated with 20 ng/ml M-CSF and RANKL. Values demonstrate mean ± SEM, * represents p<0.05.