Binding of Fabs belonging to the same stereotype to different epitopes of the same antigen. (A) Binding of subset 4-derived nFab to recombinant fragments of the subset-4 specific antigen calcyclin-binding protein. (B) Binding of subset 5-derived nFab to subset-5 specific antigen Fam32A. Antigens were coated on an ELISA and incubated with patients’ nFab. Samples U4a-c and 44 represent nFab from 4 patients with a CLL-BCR belonging to subset 4. Samples U5a-e and 21 represent nFab from 6 patients with a CLL-BCR belonging to subset 5. The numbers indicate the amino acid (aa) positions of recombinant antigen fragments.