Figure 1.

Immunostaining of CCR5-CCR2b chimeras and CCR5 point mutants with anti-CCR5 mAbs. CCR5-CCR2b chimeras are coded according to the origin of the N-terminal domain (first digit), and of the three extracellular loops (last three digits): 5555 and 2222 represent CCR5 and CCR2b, respectively; 2555 represents a chimeric receptor containing the amino-terminal domain of CCR2b and the three extracellular loops of CCR5. CCR5 point mutants are designated by the nature of their amino acid substitution. CHO-K1 cells stably expressing these constructs were stained with saturating concentrations of the different anti-CCR5 mAbs and phycoerythrin-conjugated anti-mouse IgG, and analyzed by FACS. Fluorescence histograms are shown together with the background fluorescence obtained for cells expressing CCR2b.