The BCR is downregulated in xenograft tumors treated with anti-CD79b ADCs. The xenograft tumors of BJAB-luc cells were allowed to grow to an average of 450 mm³ and then given a single dose intravenous ADC equivalent to 66.6 μg of conjugated DM1/kg mouse or unconjugated antibody at 4.5 mg antibody/kg, equivalent to the highest amount of conjugated antibody. After 48 hours tumors from 2 mice in each group were removed and analyzed by flow cytometry for surface IgM, CD79a, and CD22. (A) Plot of tumor volumes for the treated mice. Plot of the average mean fluorescence intensity of the tumors from each group for (B) IgM, (C) CD79a, and (D) CD22.