Antigen-dependence of CD19 CAR-targeted T cells in the BM.

B and congenic T cell counts from the BM of mice treated with cyclophosphamide (300 mg/kg) and increasing doses (labeled in bold) of congenic m1928z T cells. Mice were sacrificed 1 and 5 weeks after adoptive transfer with congenic T cells and flow cytometry for B cell (B220) and congenic T cells (Thy1.1/Thy1.2) was performed on single-cell suspensions of the BM. Counts were facilitated with Countbright beads (Invitrogen). E∶T ratio is the ratio of congenic donor T cells to B cells in the BM.% Dose is the m1928z T cell dose divided by the total number of BM congenic T cells, estimated by multiplying the femoral congenic T cell count by 15.8 [5].