Mice received HB-230 at a dose of 10 mg/kg via oral administration. Two hours after administration, small intestines were collected for either snap freezing or the isolation of CD45⁺ cells from the lamina propria. (A) WT ileum cryosections were costained with anti-CD103 and anti-CD11c antibodies. White arrows indicate punctate HB-230–labeled cells costained with DC markers. (B) Viable CD45⁺ immune cells were enriched from the small intestines of HB-230–dosed WT and TG2-KO mice. DCs were gated by MHCII⁺CD11c⁺F4/80^– cells, and the percentage of HB-230 among CD103⁺ cells with or without CD11b was analyzed based on PBS control (WT, n = 7; TG2-KO, n = 7). Small intestines from HB-230–administered WT mice were costained with various antibodies (Table 1) using the PhenoCycler multiplex staining system for immune cell characterization. (C) To verify that HB-230⁺CD103⁺ cells were DCs and not T lymphocytes, tissue sections were additionally stained with an anti-CD3 antibody. Yellow arrows show that HB-230 puncta colocalizes with CD103⁺CD11c⁺ DCs but not with CD3⁺CD103⁺ lymphocytes. (D) To verify that plasma cells did not take up HB-230 to form puncta, tissue sections were additionally stained with an anti-CD138 antibody. Yellow arrows denote HB-230 puncta colocalized with CD11c⁺ DCs but not with CD138⁺IgA⁺ plasma cells (indicated by white arrows). The dot plot shows the percentage of HB-230 among the cell population of each villus. P values were determined using an unpaired Mann-Whitney 2-tailed t test. **P < 0.01. Data represent mean ± SEM. A was captured under a confocal microscope at 40× magnification, and C and D were captured at 20× magnification.