Surface plasmon resonance, tetramer staining, and CD69 activation assays revealed that the PB TCR did not cross-react to other RA autoantigens, and the P-1-Cit, P2-Cit, and P5-Tyr of TNC1014,1016cit are the key determinants underlying the strict specificity of the PB TCR. The gene discussed is CD69; the disease is rheumatoid arthritis.