CD28 and B-cell chronic lymphocytic leukemia: To target the CLL-specific IGLV3-21R110 light chain mutation, we first utilized a murine IGLV3-21R110–specific antibody to generate a 2nd generation CAR with CD28-CD3ζ signaling domain for retroviral transduction of primary human healthy donor (HD) T cells (HD-αR110-mCAR1 T cells) (Fig. 1a, Supplementary Fig. 1a, b).