Primary FL cell survival in cellular capsules. (A) Imaging of purified FL B cells coencapsulated with TSC after 3 days (a) and 14 days (b) of encapsulation. Multicolor live/dead (CalceinRed/NucRed Dead) imaging of patient B cells with GFP-TSC and nuclei counterstaining with Hoechst were depicted. Spheroids were imaged on a spinning disk microscope (Aa) and on a confocal microscope (Ab) with equivalent settings (spectral windows and physical dimensions). Individual channels are depicted on the top, overlays of NucRed Dead and Calcein Red and of Hoechst and GFP on the lower panels. Individual cell analysis after 3 days (c) and 14 days (d) in culture. Renderings of nuclei centers projected in 2D as colored spheres (FL B: blue, TSC: green, Dead cells: red). Three capsules of each FL type were counted and averaged counting were plotted. (B) Evolution of the number of primary FL B cells cultured in suspension or in capsules. Cells were cultured in suspension alone or with GFP-TSC or in capsules with Matrigel and GFP-TSC for various duration. The GFP^neg FL B-cell number was determined by flow cytometry with count beads, after trypsinization of cells or capsule dissolution and Hoechst 33258 staining for gating on live cells.