Infection of lineage-specific hematopoietic cells with pseudotyped reporter viruses. (A) Approximately 2 × 105megakaryocytic (Meg colony), erythroid (Ery colony), and granulocyte-macrophage (GM colony) cells were infected with X4 or R5 Env pseudotyped viruses as indicated. Four days after infection, cells were lysed and analyzed for luciferase activity (RLU). The amphotropic MLV Env pseudotyped virus was used to control for cell viability. Megakaryocytic (B) and granulo-macrophage cells (C) were infected with either two different X4 Env pseudotyped viruses or a prototypic R5 Env pseudotyped virus, respectively, in the presence or absence of blocking agents. Leu3A is an MoAb against CD4 that recognizes the HIV Env binding epitope on CD4; SDF-1 is the natural ligand for CXCR4; R&D 701, 702, 708, and 12G5 are MoAbs against CXCR4; and R&D 531 is an MoAb against CCR5. The RLU obtained in the presence of blocking agents is normalized to the RLU obtained without any blocking agents, and the data for infection efficiency are presented as the percentage of unblocked control. Note that none of the blocking agents had any effect on the entry of the MLV pseudotyped virus, indicating the specificity of any blocking effects. All infection and blocking experiments were repeated 2 to 3 independent times with different donors with similar results. Representative experiments are shown.
