Amino acid and nucleotide sequences of the CDR3 of virtually identical Ig kappa light chains expressed by unrelated CLL patients. Alignments of the amino acid (A) and nucleotide (B) sequences of the CDR3 of the 15 V_κ A27-encoded light chains are shown, compared with CLL sample A (CLL-A). Dots indicate homology and dashes indicate no sequence at that position. Listed on the left margin is the designation for each CLL sample. Indicated on the right is the most homologous J_K gene. Underlined letters (X) designate amino acid differences between the germ-line J_K genes, relative to J_K1. Labels above indicate the relative positions of FW3, CDR3, and FW4. The sequences of the CDR3 of the SMI light chain and the germ-line sequences of V_κ A27 are included for reference.