Altered peptide ligands regulate type II collagen-induced arthritis in mice.

We reported that peripheral blood mononuclear cells from HLA-DRB1*0101 Japanese patients with rheumatoid arthritis (RA) were highly reactive to 256-271 peptide of type II collagen (CII). Similar to RA, T cells reactive to CII (AA256-271) play a crucial role in the generation of arthritis in CII-induced arthritis mouse (I-A(q)). In the present study, we regulated the CII reactivity of T cells from CIA mouse with I-A(q) by altered peptide ligand (APL). Eight different APLs were designed and screened for their antagonistic activity using CII reactive cytokine production assay. Four APLs of CII 256-271 exhibited antagonistic activity in CII-reactive T cells. Moreover, intraperitoneally injected APL-5 (G262A) significantly suppressed CII-induced arthritis in mice, whereas the other three APLs did not. Compared with the control, APL-5 suppressed interleukin (IL)-17 production by T cells from CII-induced arthritis mice. These results suggest that CII APL is a potentially suitable therapeutic strategy for the control of RA.