(A) 3D precision-cut LN slice-based organotypic cultures schematic. (B) Representative 3D image reconstruction of a human lymphoma organotypic culture stained for DLBCL cells (CD20), FRCs (PDPN), and TILs (CD8). Original magnification, ×20. (C) Confocal analysis of in situ FRCs (DLBCL-LN organotypic culture) stained for PDPN and FAP (left, 3D images; right, volume occupied analysis of FAP+ FRCs, n = 6 DLBCL patient LNs). (D) DLBCL organotypic cultures (LN57) treated for 48 hours with control antibodies (vehicle: DP47-TCB, DP47-4-1BBL, FAP-PGLALA) or with glofitamab (CD20xCD3) alone or in combination with FAP-IL2v or FAP-4-1BBL. 3D volume-rendered images show CD20+ tumor cells and cleaved caspase-3 (cCasp3) staining (upper images) and the colocalization channel (CD20+/c-Casp3+ cells) (lower). Cleaved caspase-3+ tumor cells (fold change quantification compared with vehicle treatment). Data are represented as mean ± SEM (C and D). *P < 0.05; **P < 0.01, 1-way ANOVA with Tukey’s multiple-comparisons test. Scale bars: 15 μm.