ES cells for all antibodies tested. Quite significantly, the virus conjugated with the SSEA4 and CD24 antibodies discriminated hES H9 and iPS cells from the differentiated HFF, with an average of 78% and 70% of the hES H9 and iPS cells, respectively, eGFP after infection in the presence of the CD24 antibody, compared with 1.2% of the cells eGFP on the HFF. The results for the primary fibroblasts AG1 mirrored that of the HFF. This differential for infection of hES and iPS cells over fibroblasts was not observed with the CD9 or the general HLA-1 antibody. Thus, gene delivery using the CD24 and SSEA4 antibodyconjugated targeting provides the specificity to infect the hES and iPS cells over fibroblast. All cells MedChemExpress Salianic acid A positive for infection showed.86% cell surface expression of the marker protein by flow cytometry. HFF displayed extremely low cell surface expression for SSEA4 and CD24. Targeted Gene Delivery to Human ES and iPS Cells Sensitivity of mAb-mediated selective transduction in a mixed cell population monitored by flow cytometry This differential infection of stem versus differentiated “7533610 cells was examined within a heterogeneous population, to test whether this method could identify and differentially mark stem cells for specific applications. hES H9 cells and HFF cells were mixed at different ratios and infected by m 168-pseudotyped lentiviral particles conjugated with anti-SSEA4 or anti-CD24 antibodies. Fig. 3, left shows the bright field and fluorescence images of the population mixed at 1:9 ratio of hES H9: HFF cells. For cells infected with the CD24 antibody-conjugated lentiviral particles, GFP expression clustered within cells with the H9 stem cell morphology. Anti ” SSEA4 antibodies similarly delivered GFP to H9 cells, but a 
background of GFP fibroblast can be observed. The eGFP transduction efficiency was evaluated 5 days post-infection by flow cytometry. The level of hES H9 cells within the mixed population was confirmed by flow cytometry using mouse anti-CD24 Ab/a-mouse IgG conjugated with PE. There was a direct correlation of the level of eGFP positive cells transduced through the CD24 Ab-viral conjugated with the percentage of hES H9 cells in the mixed population. In these experiments, maximal antibody-mediated GFP gene delivery corresponded to 58% of the H9 cells. These results indicate the lentiviral eGFP gene transduction in the presence of anti-CD24 antibody can specifically label hES within a hES H9 cell/HFF mixed population. Results are average of 23 infections, with average deviations indicated. Targeting and isolation of human iPS cells during reprogramming utilizing anti-CD24 Ab-mediated selective transduction The antibody-mediated gene delivery into cells expressing stem cell markers would be invaluable for the identification of iPS cells during the reprogramming process. The ability of the m 168pseudotyped lentiviral particles to selectively infect stem cell during reprogramming of human somatic cells to iPS cells was assessed. Studies were initiated to generate human iPS from African-American human primary fibroblasts by infected with M-MuLV-based retroviral vectors encoding the four defined human transcription factors Klf4, Oct4, Sox2, and c-Myc. In addition, the pMXs-Nanog vector, encoding the monomeric transcription factor Nanog, was included in order to increase the iPS induction efficiency. eGFP-IRES-Puro gene was delivered to iPS cells by anti-CD24 Ab conjugated with m 168-pseudotyped lentivirus 21 days post-in
