CD45⁺ myeloma cell lines proliferate in response to IL-6.

Flow cytometry of the indicated human myeloma cell lines stained for CD45 (A) or CD126 (IL-6Rα) (C) is shown. (B) Proliferation of human myeloma cell lines treated with (right bars) or without (left bars) IL-6 (2 ng/mL) was analyzed by BrdU incorporation, shown by mean values and SDs obtained from 3 independent experiments using triplicate samples. The CD45⁻ or CD45⁺ U266 cells were isolated by a cell sorter from parental U266 cell line.