Inhibition of angiogenesis within tumor from qVEGFR-immunized mice was estimated by immunohistochemical analysis and alginate encapsulation assay. Sections of frozen LL/2 tumor tissues obtained from mice immunized with qVEGFR (A), mVEGFR (B), and ALUM (C). Vessel density was determined by counting the number of the microvessels per high-power field (D) in tumor sections stained with Peroxidase-DAB, an antibody reactive to CD31 (brown). Original magnification, × 200 (A-C) Alginate beads containing 1 × 105 Meth A cells were implanted subcutaneously into BALB/c mice on day 7 after the fourth immunization. Twelve days later, beads were surgically removed, and FITC-dextran was quantified as described in “Materials and methods.” FITC-dextran uptake (E) and photograph of alginate implants (F) showed the reduction of vascularization in implants of qVEGFR-immunized mice.
