Figure 4.

Peptide fine specificity in the cytotoxic activity of Fab 13.4.1–PE38 on APCs. RMA-S⋅K^k cells (10⁷) were incubated overnight at 26°C with 0.1 mM Ha, NP, and mutant peptides in which 1 amino acid was changed, as shown in A. Cells were then incubated for 20 hr with recombinant Fab 13.4.1–PE38. (A) Representative cytotoxicity experiment. (B) Summary of three independent experiments. Inhibition of peptide binding to purified H-2K^k by Fab 13.4.1 was determined by competition ELISA as described (5). Percent inhibition was calculated from the data in ref. 5.