Percentage of vessel immunopositivity to HK and PK. HK results are on the top, PK results on the bottom. (A) Percentage of tumor vessels (entire endothelial cell layer) immunopositive to anti-HK in animals treated with MOPC-21 and mAb C11C1. There was a dramatic and significant decrease in the percentage of vessels positive for HK in the C11C1-treated group. (B) Representative microphotograph (cell at × 730) from animals treated with MOPC-21 showing endothelial cells staining brown (black arrows). (C) Representative microphotograph from animals treated with mAb C11C1; most vessels were immunonegative for HK. White arrows point to immunonegative endothelial cells. (D) Percentage of tumor vessels immunopositive to anti-PK in animals treated with MOPC-21 and mAb C11C1. There was a significant decrease in PK immunopositivity in the animals treated with mAb C11C1. (E) Representative microphotograph from animals treated with MOPC-21 showing endothelial cells with brown staining (black arrows). (F) Representative microphotograph from animals treated with mAb C11C1. Thirty-eight percent of the vessels examined were immunopositive to PK. The black arrow points to a positive vessel and the white arrow points to a negative vessel. The red bars in panels B, C, E, and F indicate 100 μM. The open circles in panels A and D are the mean ± SEM.