Design and properties of BARs. (A) Schematic representation of the BAR constructs containing FVIII-A2 or FVIII-C2 or OVA. (B) Representation of BAR-expressing T cells engaging with the antigen-specific B cell through their surface BCR. (C) Green fluorescent protein (GFP) expression levels in transduced mouse CD8 T cells at day 7. Inlet picture shows the fluorescent imaging of cells in culture 72 hours after transduction. (D) Single-cell imaging analysis and expression of CD8 on the surface and intracellular localization of GFP, interferon-γ (IFN-γ), perforin, and granzyme B (Gzym B) 6 hours after stimulation with anti-A2 or anti-C2 antibodies in the presence of protein transport inhibitor. Far right panel indicates the overlay of GFP, granzyme B, and perforin channels. (E) Flow cytometry analysis of C2-BAR and OVA-BAR CD8 T cells after stimulation with respective antibodies and increase in cytolytic granule proteins, such as granzyme B and perforin. Hu, human; IRES, internal ribosome entry site; PE, phycoerythrin.