TABLE 2

Expression and functional responses of wild-type and mutant receptors in transfected HEK 293T cells The binding affinity was calculated from the binding isotherms obtained with stably transfected cells. Results are expressed as means ± S.D. of three independent experiments. Selected isotherms are shown in Fig. 3. The surface expression was determined by flow cytometry on three individual clones. The representative data are shown in Fig. 2. The expression levels of the mutant receptors were normalized to that of the wild-type receptor (100%). Results are expressed as means ± S.D. of three independent experiments. The binding data for E19A and D270A were obtained with transiently transfected cells. Chemotactic activities shown are the migratory rates to 1 nM fractalkine and were calculated from Fig. 4. All activities were normalized to that induced by the wild-type receptor (100%).