![Figure 4. In vivo tumor-targeting activity of cell-internalizing mAbs. (A-D) Biodistribution of dscFvs in B16BL6 tumor–bearing mice. B16BL6 tumor–bearing mice were intravenously administered with anti-Robo4 dscFvs125I (A,C) or anti-VEGFR2 dscFvs125I (B,D). Each organ was extracted after 2 hours (A,B) or 24 hours (C,D), and the radioactivity was measured using a γ counter. %ID/g tissue was calculated using the following formula: %ID/g tissue = (count/g tissue)/(total injected count) × 100 (%). Tu, tumor; Li, liver; Ki, kidney; Sp, spleen; Lu, lung; He, heart; Br, brain; Bl, blood. (A,C) black; R4-13i[dscFv]125I; gray, R4-16[dscFv]125I; white, anti-His[dscFv]125I. (B,D) black, V2-05i[dscFv]125I; gray, V2-02[dscFv]125I; white, anti-His[dscFv]125I. Values are shown as means ± SEM. *P < .05; **P < 0.01; NS, not significant in Student’s t-test (n = 11). (E-S) Co-immunostaining of dscFvs with CD31+ blood endothelial cells on the tissue section. B16BL6 tumor–bearing mice were intravenously administered dscFvsBio. The tumor, kidney, and heart were extracted after 2 hours. Tissue sections of tumor, kidney, and heart were stained with streptavidin-PE conjugate. The blood vasculature was also stained with anti-CD31 antibody. Images were digitally merged. Red, dscFvBio; green, CD31; blue, DAPI (nucleus); yellow, colocalized region of red and green. Scale bar represents 100 μm. (E-G) R4-13i[dscFv]; (H-J) R4-16[dscFv]; (K-M) V2-05i[dscFv]; (N-P) V2-02[dscFv]; (Q-S) anti-His[dscFv]. (E,H,K,N,Q) Tumor section, (F,I,L,O,R) kidney section, and (G,J,M,P,S) heart section.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/121/14/10.1182_blood-2012-12-468363/4/2804f4.jpeg?Expires=1735824535&Signature=U~KTv0lwSb16XPEKOoh3W64eEhsaClmwAMvyhMUdSRs8fHHbOUGj3IyMCGdqlfD2RfbG1IjP0uAovLCy2KhueMzLA44EnRXcftkeqRG3HF8d~sRrDsFxe~Ftsga22V4Omq2Awww8ZKgvukQfQTwpnB1XhNh-t-mbCHVl6kBnrBpqCM0E-uvuClqQPRxa73EfAU~bqHE8xMIthK424ScyWNjrR9SUd7~fUovHDRktrSLPhJHq6Wxl-BcI8cWPIgCh-~0jePVDE4WQ2rXyfB6juxNw7zvT-mO4Z4BUdZjsl8sKEbCmY4jtS5y~itS3O0Vcq8GXqyAVTsB-TaeIND8rDQ__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
In vivo tumor-targeting activity of cell-internalizing mAbs. (A-D) Biodistribution of dscFvs in B16BL6 tumor–bearing mice. B16BL6 tumor–bearing mice were intravenously administered with anti-Robo4 dscFvs125I (A,C) or anti-VEGFR2 dscFvs125I (B,D). Each organ was extracted after 2 hours (A,B) or 24 hours (C,D), and the radioactivity was measured using a γ counter. %ID/g tissue was calculated using the following formula: %ID/g tissue = (count/g tissue)/(total injected count) × 100 (%). Tu, tumor; Li, liver; Ki, kidney; Sp, spleen; Lu, lung; He, heart; Br, brain; Bl, blood. (A,C) black; R4-13i[dscFv]125I; gray, R4-16[dscFv]125I; white, anti-His[dscFv]125I. (B,D) black, V2-05i[dscFv]125I; gray, V2-02[dscFv]125I; white, anti-His[dscFv]125I. Values are shown as means ± SEM. *P < .05; **P < 0.01; NS, not significant in Student’s t-test (n = 11). (E-S) Co-immunostaining of dscFvs with CD31+ blood endothelial cells on the tissue section. B16BL6 tumor–bearing mice were intravenously administered dscFvsBio. The tumor, kidney, and heart were extracted after 2 hours. Tissue sections of tumor, kidney, and heart were stained with streptavidin-PE conjugate. The blood vasculature was also stained with anti-CD31 antibody. Images were digitally merged. Red, dscFvBio; green, CD31; blue, DAPI (nucleus); yellow, colocalized region of red and green. Scale bar represents 100 μm. (E-G) R4-13i[dscFv]; (H-J) R4-16[dscFv]; (K-M) V2-05i[dscFv]; (N-P) V2-02[dscFv]; (Q-S) anti-His[dscFv]. (E,H,K,N,Q) Tumor section, (F,I,L,O,R) kidney section, and (G,J,M,P,S) heart section.
