IFNγ downregulates ¹²⁵I-rhEP–specific binding to ECFCs. Incubations were performed as described in Fig 3. The plateau level of ¹²⁵I-rhEP–specific binding was reached at a concentration of 0.8 nmol/L in both groups, and the level of specific binding in the rhIFNγ group (•) was lower than in the control group (○). Scatchard analysis showed high-affinity and lower-affinity classes of EP receptors, as published previously,25 and reduction of EP receptors after rhIFNγ-treatment, but no effect on the kd. A summary of triplicate experiments is shown in Table 2. ECFC purity in this experiment was 75% ± 5% in the control group and 75% ± 6% in the rhIFNγ group.