Fig. 4

Nef-induced heterologous desensitization of CXCR4. a Basophils were incubated with cell medium containing EDTA (4 mM) (white histogram) or CXCL12/SDF-1α (100 ng/ml) (grey histogram), for 30 min at 37 °C. At the end of incubation, basophils were washed twice, resuspended in Ca²⁺-containing buffer, and rechallenged with the chemotactic stimuli fMLF (500 ng/ml), CXCL12/SDF-1α (100 ng/mL), or r-Nef protein (100 ng/ml). *p < 0.05 as compared to control. b Basophils were incubated with cell medium containing EDTA (4 mM) (white histogram), fMLF (500 ng/ml) (light grey histogram), CXCL12/SDF-1α (100 ng/ml) (black histogram) or r-Nef protein (100 ng/ml) (grey histogram), for 30 min at 37 °C. At the end of incubation, cells were washed twice, resuspended in Ca²⁺-containing buffer, and challenged with the chemotactic stimuli CXCL12/SDF-1α (100 ng/ml) or r-Nef (100 ng/ml). Values are the mean ± SEM of three distinct experiments. *p < 0.05 as compared to basophils preincubated in the absence of chemotactic stimuli