Figure 3. Identification of Be-dependent naturally occurring peptides that stimulate T cell hybridomas expressing the LKGGG CDR3β motif.

(A) Sequence logos summarizing hybridoma responses to the D5E8 PSL are shown, depicting amino acids fixed at the listed peptide position by hybridoma activity. Only amino acids with greater than 25% of maximal activity for each hybridoma are shown, and the height of each amino acid (single-letter code) corresponds to the activity of the peptide. If no amino acids are displayed, none met the threshold. The color of each letter groups amino acids by their chemical characteristics. (B) Response of 8 hybridomas expressing LKGGG CDR3β TCRs to naturally occurring peptides plus BeSO₄ presented by HLA-DP2–transfected fibroblasts. Peptides are ordered by their biometrical analysis ranking and are included on the list only if at least one of the hybridomas demonstrated a positive response (>200 pg/mL IL-2 at 1.0 μg/mL peptide). Intensity of green color highlights peptides inducing the highest IL-2 secretion. The protein source of each peptide is indicated by its UniProt identification number and name. (C) UniProt number and amino acid sequence of related human chemokine peptides derived from CCL4 and CCL3 (biometrical analysis peptides BA001 and BA002, respectively).