Figure 1: (A) Dose-dependent binding between rat anti-id Mabs in cell supernatants and microwell-coated RP215 F(ab)2 on ELISA described in the text. Alkaline phosphatase-labeled goat anti-rat IgG was used as the secondary antibody for signal detection at 405 nm; (▲), (♦) and (■) denote Rat anti-id Mabs, R3E4, R3E7 and R15H6 in cell culture medium (RPMI1640 plus 10% fetal calf serum), respectively (estimated Kd for R15H6 binding to RP215-F(ab)2 : = 1 10-9M). Normal rat IgG (10g/ml) in cell culture medium (RPMI1640 plus 10% fetal calf serum was used as the negative control. Data presented are those substrated from the negative control (OD=0.1). (B) Dosedependent activities for rat anti-id Mabs R3E4 (▲), R3E7 (♦) and R15H6 (■), as well as CA215 (●) in RPMI1640 cell culture medium (10%fetal calf serum) on RP215-based sandwich EIA as described in the text. Normal rat IgG (10g/ ml) in the same culture medium served as the negative control. Data presented are those subtracted from the negative control (OD=0.1).