Extended Data Fig. 5: apMCs spatially localize with and potentiate T cell immunity in mouse TNBC.
(a, b) A representative image of CD74 and tryptase multiplex immunofluorescence (a), and mast cell subtypes in mouse TNBC (b, n = 6). (c) A representative enlarged image of CD4, CD8, CD74, and tryptase multiplex immunofluorescence in mouse TNBC (n = 6 biological replicates in Fig. 3c). (d) Scaled deconvolution values for apMC and T cell overlay onto tissue spots using spatially resolved transcriptomics. (e) Spatial pattern of apMC and T cell localization. (f) Mast cells other than apMCs were enriched to greater than 95% purity. Numbers indicate percentages of cells in the gates. (g) Composite data of six experiments representing activation marker CD69 expression by OT-II CD4+ T cells primed by relative mast cells cocultured with OVA-expressing or control AT3 cells. (h) Composite data of six experiments representing proliferation (Ki67), activation (CD69), and effector function (IFN-γ, IL-2) of OT-I CD8+ T cells primed by relative mast cells pulsed with tumor lysates of OVA-expressing or control AT3 cells. (i) Distribution of apMC signature in mouse TNBCs responsive (n = 22) or resistant (n = 25) to ICI therapy. (j, k) Tumor cells (j, E0771, n = 5; k, AT3, n = 6) alone or mixed with indicated mast cells were orthotopically injected into B6.Cg-KitW-sh mice, which then received 10 mg/kg anti-PD-1 antibody or IgG isotype. Tumor weights at the endpoint in each group were shown. (l) Flow cytometry of infiltration and functional states of T cells in tumors from each treatment group in (k). (m) Representative flow cytometry plots of surface activation markers in tumor-infiltrating T cells from different treatment groups in (l). (n, o) Growth curves and tumor weights at the endpoint in mice induced with apMC-enriched tumor contexture or in combination with 10 mg/kg CD8 (n, n = 6) or CD4 (o, n = 5) neutralizing antibody in the 4T1 orthotopic tumor model (IgG as isotype control). Data are mean ± s.e.m. (g, h, j–l, n, o) and error bands of the line plot indicate 95% CI (e). Box plots show the median (center line) and interquartile range (bounds of box) as well as the minima and maxima (whiskers) (i). Two-sided unpaired Student’s t-test (g–l, n, o for tumor weight), two-way ANOVA (n, o for tumor volume).
