Be-specific T cell hybridoma response to alanine substitutions and analogues of mimotope-4. Peptide dose–response curves were completed for T cell hybridoma AV22. (A–C) Equal numbers of AV22 cells and DP2.21 antigen-presenting cells were mixed with 75 µM BeSO₄ and the following highly purified peptides: peptides with single alanine substitutions at each position of mimotope-4 (A), analogues of mimotope-4, selected based on the demonstrated potency of other mimotopes (B), and mimotope-4 variants at the p2 position of the peptide (C). IL-2 secretion was measured by ELISA after 22 h of culture, and data are plotted as the percentage of maximum IL-2 secretion against peptide concentration in the presence of BeSO₄. EC₅₀ values (mean ± SEM nM) for mimotope-4 and each variant peptide from four independent experiments are shown. Note that error bars have been left out for viewing clarity. (D) Correlation of EC₅₀ values of all variants of mimotope-4 between hybridomas AV22 and AV9.