Figure 4. Leukemia xenograft growth is reduced in mice treated with 91R mAb. For xenograft analyses, MOLT-4 cells were inoculated s.c. in Rag2^−/− mice on day 0 (d0). Experimental groups received four i.p. doses of 91R or irrelevant IgG2b mAb (first and second, 4 mg/kg; third and fourth, 2 mg/kg). Tumor growth was measured with a caliper every three days. After mice were sacrificed, tumors were removed and weighed. (A) Antibody administration schedule on days 1, 7, 14 and 21 for mice bearing tumor cells injected in each flank. (B) Tumor growth kinetics. Tumor volume was measured at times indicated and calculated as V = [axial diameter length, mm] x [(rotational diameter, mm)²/2] (6 mice/group). (C) Tumor weight (%) relative to IgG2b treatment on d56. Mean ± SEM (n = 6 mice/group). (D) Images of tumors from IgG2b- and 91R-treated mice at the time of sacrifice (day 56). Bar = 1 cm. (E) Antibody administration schedule on days 7, 14, 21, and 28 in mice injected only in one flank. (F) Tumor volume was calculated as in B (10 mice/group). (G) Percentage of tumor weight relative to IgG2b treatment on d69. Results show mean ± SEM (n = 10 mice/group). (H) Images of tumors from IgG2b- and 91R-treated mice at the time of sacrifice (day 69). Bar = 1 cm. *** P < 0.001, ** P < 0.01, * P < 0.05.