Effect of bone marrow-derived CD11b⁺F4/80⁺ immature dendritic cells on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis

Objective: To explore the effect of bone marrow-derived CD11b ⁺F4/80⁺ immature dendritic cells (BM CD11b ⁺F4/80⁺iDC) on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis (CIA). Methods: BM CD11b⁺F4/80⁺iDC were induced with rmGM-CSF and rmIL-4, and were identified by the expressions of toll-like receptor 2 (TLR-2), indoleamine 2,3-deoxygenase (IDO), interleukin (IL)-10, transforming growth factor (TGF)-β1 and mixed leukocyte reaction (MLR). CIA was established in DBA/1 mice by immunization with type II collagen. CIA mice were injected intravenously with BM CD11b⁺F4/80⁺iDC three times after immunization. The effect of BM CD11b⁺F4/80⁺iDC on CIA was evaluated by the arthritis index, joint histopathology, body weight, thymus index, thymocytes proliferation, IL-1β, tumor necrosis factor (TNF)-α, IL-17, IL-10 and TGF-β1 levels. Results: BM CD11b ⁺F4/80⁺iDC induced with rmGM-CSF and rmIL-4 expressed high levels of TLR-2, IDO, IL-10 and TGF-β1. Infusion of BM CD11b ⁺F4/80⁺iDC in CIA mice significantly reduced the arthritis index and pathological scores of joints, recovered the weight, decreased the thymus index and inhibited thymocyte proliferation. Levels of IL-1β, TNF-α and IL-17 were decreased in BM CD11b⁺F4/80 ⁺iDC-treated mice. Conclusions: BM CD11b⁺F4/80 ⁺iDC can be induced successfully with rmGM-CSF and rmIL-4. BM CD11b⁺F4/80⁺iDC treatment can ameliorate the development and severity of CIA by regulating the balance between pro-inflammatory cytokines and anti-inflammatory cytokines.