Fig. 2: αCD38 antibody treatment reduces CD38 expression and increases stemness genes in CTCL cells.

A Schematic representation of the experimental design for in vivo testing. CD38+ luciferase expressing CTCL cells (H9 line) were engrafted intravenously in immunodeficient NRG mice which were randomly assigned to treatment conditions with either αCD38 antibody (daratumumab; 100 mg/kg subcutaneously weekly for four weeks) or IgG isotype control (0.8 mg/kg subcutaneously once a week for four weeks). Tumor burden was measured over time using IVIS imaging and quantified using Living Image software. B Representative images of mice treated with isotype or αCD38 antibody and quantification of tumor burden total flux (photons/second) at 19 days post-engraftment. αCD38 antibody treatment resulted in an average total flux = 1.4e7 photons/sec (N = 4), while IgG average total flux = 9.0e7 photons/sec (N = 3); p = 0.0002. C Flow cytometry analysis of tumor cells isolated from the bone marrow of mice, performed 28 days post-engraftment after three weeks of treatment with either IgG isotype control (N = 5) or αCD38 (N = 7). Lymphocytes were gated for human CD45+ cells and analyzed for human CD38 signal. D Quantification of the percentage of CD45+ tumor cells expressing CD38 based on the data from panel (C) (p < 0.0001 by unpaired t test). E qPCR analysis of the relative expression of CD38, B-catenin (CTNNB1), TCF7, and BCL6 genes in CTCL tumor cells isolated from the bone marrow of mice that were treated with either isotype or αCD38 antibody (p < 0.0001 in all conditions by 2way ANOVA).