Fig 2: Decellularized lymph nodes can be used to induce the infiltration of immune cells in vivo. (a) Diagram of the dLNs transplantation into the back of mice. (b) HE staining of frozen LNs (left) and dLNs (right) transplanted into the backs of mice for 4 weeks. Scale bar = 1000 μm or 100 μm. (c) The multiplex immunofluorescence results of CD20, CD4, and CD3 for frozen LNs (left) and dLNs (right) transplanted into the backs of mice for 4 weeks. Scale bar = 100 μm. (d) CD20, CD4, and CD3 immunohistochemistry results of dLNs (above) and frozen LNs (below) transplanted into the backs of mice for 4 weeks. Scale bar = 100 μm. (e) Comparison of integral optical densities of CD3, CD4, and CD20 in dLNs and frozen LNs (n = 5/group). * indicated p < 0.05, ** indicated p < 0.01. LNs, lymph nodes; dLNs, decellularized lymph nodes. The student's t‐test was used to compare dLNs to frozen LNs treated mice.

Fig 3: Cytological experiments and mIHC confirmed that TREM1+ Mφ promoted pathogenic Th17 cell differentiation triggered by epithelial pyroptosis.a Flow chart of cytological experiments. b Flow cytometry showing the TREM1 expression of the TREM1+ Mφ and TREM1NC Mφ. c Elisa assay depicting the concentration of IL-1β in TREM1+ Mφ and TREM1NC Mφ with/without the stimulation of recombinant human HMGB1 (rhHMGB1), respectively. Note: **p < 0.01, NS not statistically significant. Flow cytometry (d) and statistical analysis (e) of the cell proportion of CD4+ IL-17A+ cells, CD4+ IL-17F+ cells, and CD4+ IL-22+ cells after murine naïve CD4+ T cells co-cultured with the supernatants of TREM1+ Mφ, IL-6 and IL-23, with/without neutralizing anti-IL-1β (α-IL-1β). Note: *p < 0.05, **p < 0.01, NS not statistically significant. f Representative images of mIHC in NREOLP (top) and REOLP (bottom). Scale bars: 100 µM (top) and 50 µM (bottom). Yellow arrows pointed to LPS+ GSDMD+ E-cad+ cells. Red arrows pointed to TREM1+ CD68+ cells. Green arrows pointed to IL-17A+ CD3+ cells.