Collagen alpha-1(II) chain (CII) (CII)

Collagen alpha-1(II) chain, commonly known as Collagen type II, is the primary structural protein of hyaline cartilage and a major autoantigen in the development of rheumatoid arthritis (Source: UniProt P02458). In the context of immunotherapy, the oral administration of this protein is used to induce a state of peripheral immune unresponsiveness known as oral tolerance (Source: Weiner, H. L., Nature Reviews Immunology, 2001). This process is mediated by the induction of antigen-specific regulatory T cells (Tregs), including CD4+CD25+Foxp3+ cells and Th3 cells, within the gut-associated lymphoid tissue (Source: Min, S. Y., et al., Arthritis Research & Therapy, 2004). These Tregs migrate to the systemic circulation and inflamed joints, where they suppress the autoimmune attack on endogenous cartilage through the secretion of anti-inflammatory cytokines like TGF-beta and IL-10, a phenomenon termed bystander suppression (Source: Park, M. J., et al., Immunology Letters, 2009). Therapeutic agents targeting this pathway, such as native type II collagen supplements or investigational oral formulations, aim to restore immune homeostasis in patients with autoimmune joint diseases (Source: Zhu, P., et al., Chinese Medical Journal, 2001). Despite promising results in animal models of collagen-induced arthritis, clinical efficacy in humans has been variable, highlighting the importance of dosage and protein conformation in achieving a tolerogenic effect.

Other names

Type II collagenCollagen alpha-1(II) chainCOL2A1Cartilage collagenAlpha-1 type II collagen

Induction of oral tolerance via the activation of antigen-specific regulatory T cells (Tregs) in the gut-associated lymphoid tissue, which subsequently suppress systemic autoimmune responses through the secretion of TGF-beta and IL-10.