Impact of rituximab blocking on tumor control by CD20 and CD45-directed radioimmunotherapy. (A) B-NHL (Granta) xenograft volume after pretreatment with 400 μg 1D8 (control antibody) followed by therapy with 14.8 MBq (400 μCi) ¹³¹I-BC8, 14.8 Mbq (400 μCi) ¹³¹I-tositumomab, or no treatment. (B) B-NHL (Granta) xenograft volume after pretreatment with 14.8 Mbq (400 μCi) rituximab followed by therapy either with 14.8 Mbq (400 μCi) ¹³¹I-BC8, 14.8 Mbq (400 μCi) ¹³¹I-tositumomab, or no treatment. Error bars represent SE.