Binding of human anti-T-cell receptor (TCR) monoclonal autoantibodies (mAAbs) to peptides specifying the complementarity determining region 1 (CDR1) segments of murine Vβ gene products. OR2, OR5 and Syn 2H-11 anti-TCR mAAbs were examined by enzyme-linked immunosorbent assay (ELISA) for binding to peptides corresponding to the mouse Vβ 8 CDR1 region. Binding of titrated antibody concentrations, in µg/ml, (abscissa) was determined according to the absorbance signal (ordinate) generated by enzyme-linked secondary anti-human immunoglobulin M (IgM) conjugate. The vertical line on the abscissa after the zero point indicates that antibody titrations were not extrapolated to zero. (▪), ms Vβ 4; (○), ms Vβ 8.1 HV short; (▵), ms Vβ 8.2 HV short; (+), ms Vβ 8.2 long; (×), ms Vβ 1 HV.