Figure 1. Localization and Expression of Key Tissue-Residency Markers on T Cells in Human Pancreas.

(A) Representative qmIF composite image of a pancreas section stained with antibodies specific for CD3 (purple), the ductal marker CK19 (green), DAPI nuclear counterstain (gray), and the neuroendocrine marker chromogranin (white) are shown (left) adjacent to a representative single color CD3 image (middle). Acinar, ductal, and endocrine areas were defined based on CK19 and chromogranin staining. White bar, 100 µm for scale. Right: densities of CD3⁺ T cells were quantified in the three regions of pancreas using inForm software. Plots show mean ± SEM from 13 donors.

(B) T cells were analyzed in cell suspensions of pancreas (Panc), jejunum (Jej), pancreas-draining lymph node (PLN), and mesenteric lymph node (MLN). Shown are representative (left) and the compiled (right) CD4 and CD8 T cell frequencies (gated on DAPI^lo CD45⁺CD3⁺ cells) from the four tissue sites. Bars indicate comparisons for CD8⁺ T cells.

(C) Expression of CD69 in conjunction with TRM signature markers CD103, CD49a, and PD-1 on CD8⁺ TEM cells (CD45RA⁻CCR7⁻) subsets isolated from indicated sites shown as representative flow cytometry plots (left) with the compiled frequencies ±SEM of the indicated subsets from three to eight donors (right). Bars indicate comparisons of the CD69⁺CD103⁺ (top), CD69⁺CD49a⁺ (middle), and CD69⁺PD-1^hi (bottom) subsets.

(D) Expression of intracellular granzyme B (GZMB) in CD8⁺CD69⁺TEM cells isolated from pancreas, jejunum, and PLN shown as representative flow cytometry plots (left), and compiled frequencies ± SEM of GZMB⁺ cells from three to six donors for each tissue (right). Bars indicate comparisons of the GZMB⁺ frequencies within the indicated subsets.

**p < 0.001 as calculated by two-way ANOVA with Dunnett’s multiple comparisons test.

See also Figure S1.