Figure 4.

QL9/L^d binding by soluble scTCRs. T2-L^d cells loaded with QL9 were incubated with ¹²⁵I-labeled anti-L^d Fab fragments (30–5-7) and various concentrations of unlabeled Fab (□), scTCR-T7 (■), or mutant scTCR-m6 (●). Bound and unbound [¹²⁵I]30–5-7 Fab fragments were separated by centrifugation through olive oil/dibutyl phthalate. Binding of ¹²⁵I-labeled anti-L^d Fab fragments to T2-L^d cells loaded with the control peptide MCMV was not inhibited even at the highest concentrations of scTCRs (data not shown).