Fig. 2: Monitoring CAR T cell dynamics in the leukaemia bone marrow niche on-chip.
a, Leukaemia burdens of leukaemia chips treated either with 10,000 of CAR or Mock T cells (effector-to-tumour cell ratio = 1:1), or left untreated. Data were collected from four technical replicates (n = 4), mean and s.e.m. b, Representative images showing CAR T cell extravasation (top) and killing of B-ALL (bottom). The white arrows indicate T cells. Representative images were from one of the three technical replicates with similar results (n = 3). c, Comparison of T cell migration dynamics. Representative trajectories of 10 Mock T cells (top left) and 10 CAR T cells (bottom left) monitored for a 4 h period after on-chip infusion for 2 days. Data (right) were collected from four technical replicates (n = 4) with >100 T cells. Unpaired two-sided, Student’s t-test, mean and s.e.m. d, The formation of synapse between CAR T cell and leukaemia cell (CD19+ in orange) on-chip surrounded by CD31+ vascular cells. Representative images were from one of the three technical replicates with similar results (n = 3). e, Surface expressions of T cell activation marker CD25 on CAR T cell in different groups on day 2. Data were collected from six independent experiments (n = 6). One-way ANOVA followed by Tukey’s post hoc test, mean and s.e.m. f, Surface expressions of T cell activation marker CD69 on CAR T cell in different groups on day 2. Data were collected from six independent experiments (n = 6). One-way ANOVA followed by Tukey’s post hoc test, mean and s.e.m. g, ELISA measured secretions of IFNγ from leukaemia chips on day 1 and day 2. Data were collected from eight independent experiments (n = 8). Two-way ANOVA followed by Tukey’s post hoc test, mean and s.e.m. h, scRNA-seq mapping of bone marrow niche treated with CAR T cell on-chip for 2 days. i, Cellularity of samples collected from leukaemia chips treated with CAR or Mock T cell. Red boxes indicate CD19-expressing populations. j, Dot plot representation of mRNA expression levels of IL2RA, CD69 and MKI67 in CAR and Mock T cell. k, Analysis of DEGs in CAR T cells before (off-chip) and after activation (on-chip). Two-sided Wilcoxon rank sum test. l, KEGG pathway analysis revealed enhanced signalling pathways in CAR T cells before (off-chip) and after activation (on-chip). Two-sided Wilcoxon rank sum test.
