Functionality of B and T-cell lineages derived from teratoma. (A) ELISA assay showing CD19⁺ B cells-Ter produce NS5 IgG and total human IgG in amounts comparable with those produced by CD19⁺ cells isolated from human peripheral blood (left panel). Murine CD19⁺ B cells were isolated and cultured in the same conditions and used as negative control (middle panel). CD19⁺ B cells derived from transplanted Ter and CB-CD34⁺CD45⁺ produce a similar total human IgGs (right panel). Absorbency at 450 nm is shown in the y-axis. (B) Typical CD3⁺ T cells^Ter morphology after isolation from teratoma parenchyma and culture with IL-2 and anti-CD3 beads. (C) Quantitative cytokine assay showing that T cells^Ter produce cytokines when stimulated with IL-2 and anti-CD3 beads. The amounts of cytokines secreted were comparable with those secreted by the same number of CD3⁺ cells isolated from human peripheral blood (left panel). CD3⁺ T cells isolated from NSG transplanted with cord blood and teratoma HSPCs were isolated from murine spleens after 60 days of transplantation and evaluated for cytokine production (right panel). Error bars represent SD for both experiments. (D) Fluorescents latex bead-phagocytosis assay for CD15⁺ cells derived from teratoma (Ter) and of CD15⁺ derived from human PB. The right panel shows representative CD15⁺ cells after immunofluorescent bead uptake.