“…Compounds and Antibodies-CXCL12 (PeproTech, Hamburg, Germany), 125 I-CXCL12 (ARI0129, Hartmann Analytic, Braunschweig, Germany), AMD3100 (A5602, Sigma), cycloheximide (C4859, Sigma), -protein phosphatase (P0753, New England Biolabs GmbH, Frankfurt am Main, Germany), CCX733 and 11G8 monoclonal mouse anti-CXCR7 antibody (ChemoCentryx, Mountain View, CA) (22), anti-transferrin receptor antibody (13-6800; Invitrogen), and UMB-2 monoclonal rabbit anti-CXCR4 antibody (23). Polyclonal rabbit antisera against the hemagglutinin (HA) epitope MYPYDVPDYA were generated by injecting the peptide into rabbits 631-633 after coupling to keyhole limpet hemocyanin and emulsification with Freund's adjuvant.…”