Intravenous Immunoglobulin Controls Th17 Cell-Mediated Osteoclastogenesis

Area of Science:

• Immunology
• Cell Biology
• Rheumatology

Background:

• Th17 cytokines play a role in inflammatory bone diseases.
• Osteoclast differentiation is crucial for bone remodeling and resorption.
• Understanding regulatory mechanisms of osteoclastogenesis is vital for treating bone-related disorders.

Purpose of the Study:

• To investigate the regulatory role of intravenous immunoglobulin (IVIg) in Th17 cytokine-induced RANK ligand (RANKL) expression.
• To determine the effect of IVIg on osteoclast (OC) differentiation from OC precursors (pre-OC).
• To explore IVIg's impact on Th17 cell differentiation and polarization.

Main Methods:

• Human CD14+ monocytes were isolated and stimulated with Th17 cytokines (IL-17, IL-21, IL-22).
• RANKL expression was quantified using real-time PCR.
• Osteoclast differentiation was assessed by counting tartrate-resistant acid phosphatase-positive multinucleated cells after co-culture with RANKL, Th17 cytokines, or Th17 cells, with or without IVIg.
• Th17 cell differentiation was analyzed using ELISA and flow cytometry.

Main Results:

• Th17 cytokines stimulated monocytes to express RANKL; IVIg suppressed this induction.
• IVIg reduced osteoclastogenesis induced by RANKL, Th17 cytokines, and co-culture with Th17 cells.
• IVIg significantly decreased Th17 and Th1 cell differentiation but did not affect Treg cell differentiation.

Conclusions:

• IVIg effectively inhibits Th17 cytokine-induced RANKL expression and subsequent osteoclast differentiation.
• IVIg demonstrates a suppressive effect on osteoclastogenesis mediated by Th17 cells.
• IVIg's ability to reduce Th17 polarization suggests its potential as a therapeutic agent for Th17 cell-mediated bone diseases.