CD19 expression in KMS-5 human myeloma cell line leads to growth inhibition in vitro. K-19⁺, K-▵19, and neo-control clones were adjusted to 1 × 10³/mL and plated in RPMI 1640 + 10% FCS. Cells were harvested and counted at the indicated time points both automatically on the cell sorter and manually on a hemocytometer. Data from 3 experiments are shown as mean ± standard deviation (SD).