Interaction between CD19-CAR-T Cells and CD19-Expressing β-like Cells in Transplanted Mice
(A) Top panel: in vivo detection of β-like INS reporter cells engrafted under the kidney capsule of immunocompromised NSG mice. Bottom panel: luciferase signal changes in mice that received a transplant upon infusion of CD19-CAR-T cells or CTL-CAR-T cells, as labeled.
(B) Representative confocal microscopy of transplanted β-like cells. Scale bar, 20 μm.
(C) Infiltration of human CD8-T cells (red) in the kidney transplanted with INS:tdT β-like CTL cells (left panel) or with INS:CD19 β-like cells (right panel). Scale bar, 20 μm.
(D) Representative RNA-seq results of the CD274 (PDL1) locus in β-like cells (top two panels) and primary islets (bottom two panels) when treated with CTL medium (black tracks) or reactive T cell-conditioned medium (red tracks).
(E) qRT-PCR analysis of PDL1 expression in primary human islets (left panels) and β-like cells (right panels) when treated with CTL medium (open bars) or reactive T cell-conditioned medium (filled bars) (n = 4).
(F) Left panel: experimental design. Right panels: representative immunofluorescence micrographs of CD19-expressing β-like cells engrafted in mice without CD19 CAR-T cell infusion (top panels) and upon CD19-CAR-T cell infusion (center panels). Bottom panels: mice engrafted with PDL1- and CD19-expressing β-like cells. Scale bar, 10 μm.
(G) Left panel: experimental design. Right panels: in vivo luciferase imaging before T cell infusion (day 0) or 10 days after T cells infusion (day 10). The results are quantified in (H) (n = 4).
(I) Representative confocal micrographs of C-peptide-expressing β-like cells (green) and infiltrating human CD8+ T cells (red). Scale bar, 20 μm.
(J) Coculture of PDL1- and CD19- expressing β-like cells with CD19-CAR-T cells showed reduced IL-2 secretion compared with CD19-expressing β-cells that do not overexpress PDL1 (n = 4).
In (H): ∗p < 0.05, Wilcoxon-Mann-Whitney test. Other: ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, non-paired t test.
See also Figures S5 and S6.