Attenuation of collagen-induced arthritis in 55-kDa TNF receptor type 1 (TNFR1)-IgG1-treated and TNFR1-deficient mice

Area of Science:

• Immunology
• Rheumatology
• Molecular Biology

Background:

• Tumor necrosis factor (TNF) is a key inflammatory cytokine implicated in various autoimmune diseases.
• Collagen-induced arthritis (CIA) is a widely used mouse model to study rheumatoid arthritis pathogenesis.
• The specific role of TNF and its receptor, TNFR1, in CIA initiation and progression requires further elucidation.

Purpose of the Study:

• To investigate the role of TNF and TNFR1 in the pathogenesis of collagen-induced arthritis (CIA) in mice.
• To determine whether TNF neutralization or TNFR1 deficiency affects CIA development and severity.
• To understand the distinct roles of TNFR1 in CIA initiation versus disease progression.

Main Methods:

• DBA/1 mice were immunized with type II collagen and treated with TNFR1-IgG1 fusion protein to neutralize TNF.
• TNFR1-deficient mice were generated and crossed with DBA/1 mice to study CIA development in the absence of TNFR1.
• Clinical scoring and histological analysis were performed to assess arthritis incidence, severity, and joint damage.

Main Results:

• Treatment with TNFR1-IgG1 fusion protein shortly before disease onset prevented CIA, indicating TNF's critical role in late initiation.
• TNFR1-deficient mice developed CIA with lower incidence and milder symptoms compared to wild-type mice.
• Once arthritis was established in TNFR1-deficient mice, disease progression led to similar end-stage joint destruction as in wild-type mice.

Conclusions:

• TNFR1 acts as the primary transducer of TNF's pro-inflammatory effects in the establishment of CIA.
• The progression of CIA to tissue destruction and ankylosis is independent of TNFR1 signaling.
• Targeting TNF or TNFR1 may be effective in preventing CIA onset but not necessarily in halting established joint damage.