Figure 3 Binding of calpastatin peptides to HLA‐DR alleles. ELISA plates were coated with 10 µg of calpastatin peptide per well. One microgram of purified HLA‐DR molecule was then added to plates. After washing, bound HLA‐DR was detected by biotinylated anti‐HLA‐DR antibody followed by peroxidase conjugated avidin. The optical density was read at 405 nm. Positive binding was defined as an OD value higher than twice the OD for HLA‐DR without peptide. HLA‐DR specific peptide defined a peptide that binds only one HLA‐DR allele.