Fig. 1
Expression of recombinant fusion proteins in engineered MSCs. (A) The morphology and fluorescence microscopy imaging of UCMSCs transfected with Tandab-expressing or empty lentiviral vector. Scale bar = 50 μm. (B) Flow cytometry analysis of copGFP-positive UCMSCs. (C) Cell survival of UCMSCs with or without lentivirus transduction was assessed using the CCK8 assay. (D) Western blot analysis was employed to determine the protein expression of Tandab (CD3/BCMA) in UCMSCs using anti-His tag antibodies following 3 days after transduction. Target bands are indicated by blue arrows. BME, β-mercaptoethanol. Lane 1, MSCs transfected with empty vector (negative control); lane 2, MSCs transfected with vector expressing Tandab (CD3/BCMA). Full-length blots/gels are presented in Supplementary Figure S1. (E) Transduced UCMSCs consistently secreted Tandab (CD3/BCMA). MSC-Tandab and MSC-EV were cultured in a 24-well plate (4 × 104 cells/well), and the level of Tandab (CD3/BCMA) released into the culture supernatant was measured by ELISA at the indicated time points. Data are shown as the means ± SD of the three repeated experiments