All of the following stimulate osteoclast activity EXCEPT:

Osteoclast activators include: TNF-beta (A — stimulates osteoclasts), IL-1 (B — major bone resorption cytokine), PTH (D — parathyroid hormone increases osteoclast activity), RANKL (E — RANKL/OPG axis is the primary regulator, RANKL stimulates osteoclastogenesis). IL-8 (C) is a NEUTROPHIL CHEMOTACTIC FACTOR — it recruits neutrophils to sites of infection/inflammation but is NOT a primary OSTEOCLAST STIMULATOR. IL-8 does not significantly stimulate osteoclast differentiation/activity. C is the EXCEPT answer.