Figure 4.

Inhibition of osteoclastogenesis by iNKT cells via IFN‐γ production. A, In healthy controls (HCs), the level of IFN‐γ in osteoclasts (OCs) culture supernatants at day 7 and day 14 markedly increased in α‐GalCer‐stimulated cultures compared with DMSO control cultures. The differences at day 7 were significant, but at day 14 were no significant. About the level of TNF (B) and IL‐13 (C) in OCs culture supernatants, no significant differences were found between α‐GalCer‐stimulated cultures and DMSO control cultures at day 0, day 3, day 7 and day 14 in NDMM patients and HCs. Mean ± SEM between the experimental samples were compared using Student's t test. D, Representative tartrate‐resistant acid phosphate (TRAP)‐positive multinucleated cells (MNC) from a NDMM patient in the presence or absence of recombinant IFN‐γ or α‐GalCer and a HC in the presence or absence of anti‐IFN‐γ or α‐GalCer. Original magnification × 100 (Bar = 100 μm). E(a), The number of TRAP ⁺ MNCs was significantly increased in the presence of anti‐IFN‐γ and α‐GalCer cultures compared with the presence of α‐GalCer cultures (b) The number of TRAP ⁺ MNCs was significantly reduced in the presence of IFN‐γ and α‐GalCer cultures compared with the presence of α‐GalCer cultures. Mean ± SEM of each group were compared using one‐way ANOVA analysis. F, The mRNA expression of osteoclast‐associated genes, such as TRAP, osteoclast‐associated receptor (OSCAR) and RANKL was significantly improved in the presence of anti‐IFN‐γ and α‐GalCer cultures compared with the presence of α‐GalCer cultures. Medians of each group were compared using Kruskal‐Wallis test followed by all pairwise multiple comparisons. G, The mRNA expression of RANKL was significantly decreased in the presence of IFN‐γ and α‐GalCer cultures compared with the presence of α‐GalCer cultures. Medians of each group were compared using Kruskal‐Wallis test followed by all pairwise multiple comparisons (*P < .05, **P < .01, ***P < .001)