Anti cd71 and anti ter119 antibodies

Infected cells were cultured in expansion medium at an initial cell density of 05 × 10⁶ cells/ml for three days as previously described (Zhang et al, 2019 (link)), and collected daily for analyses. Proliferation of infected cells, which were GFP⁺, was determination by counting the nucleated cells with crystal violet stain using haemocytometers and then multiplying the percentage of GFP⁺ cells from flow cytometry analysis. Erythroid differentiation was performed as previously described (Zhang et al, 2018 (link), 2019 (link)). Briefly, cells were labelled with anti-CD71 and anti-Ter119 antibodies (BioLegend, San Diego, CA, USA). 4’,6-diamidino-2-phenylindole (DAPI; Roche, Basel, Switzerland) was used to exclude dead cells. Infected GFP⁺ live cells were gated for erythroid differentiation analysis by flow cytometry using FACS LSR II (BD Biosciences, San Jose, CA, USA), and data were analysed with FlowJo (Tree Star, OR, USA). Erythroid differentiation was also analysed by cell morphology on cytospin slides stained with May-Grunwald/Giemsa staining (Sigma-Aldrich).