Figure 6.
CD47 inhibits DsRed expression by macrophages in vivo and enhances DsRed expression in human tumor cells. (a) 1 × 109 CD47- or control Lenti were injected via tail-vein. Spleens were mechanically dissociated 5 days postinjection. Splenic macrophage were identified by F4/80 immunostaining, and analyzed for DsRed transgene expression by flow cytometry. CD47-Lenti injected spleens showed decreased splenic macrophage transduction. (b) 1 × 109 CD47- or control Lenti were injected via tail-vein. 5 days postinjection livers were isolated. Tissue sections were imaged for RFP expression by confocal microscopy. Cells that were consistent with Kupffer cell morphology (Supplementary Figure S5a–d) and positive for RFP expression were quantified. (c) CD47- or control Lenti were injected via tail-vein to A549 xenograft-tumor bearing NSG mice, and 4 days postinjection tumors were isolated and analyzed for RFP transgene expression where CD47-Lenti mediated significantly higher transgene expression. For all, n ≥ 6 unless indicated; P ≤ 0.05. (d) Analysis of the huCD47-neg, muSIRPA-neg cells in the tumor indicated that CD47-lenti showed lower percent transduction of this mouse tumor stroma cell subset.