Figure 4. CD146 deficiency of donor T cells is associated with decreased pathogenic IFN-γ⁺IL-17⁺ T cells and macrophage infiltration, but an intact TFH–GC B cell axis.

(A) Flow cytometry was performed on single-cell suspension from lungs of different animal groups analyzed by flow cytometry at day 56, after stimulation with PMA-ionomycin in the presence of protein transport inhibitor. Data represent frequencies (mean ± SEM) of IFN-γ⁺IL-17⁺ subset within CD146⁺ (left panel) or CD146⁺CCR5⁺ fractions (right panel). (B) Lung cryosection were stained for CD68 expression (macrophages) together with DAPI to quantify cellular infiltrate. A representative example of immunofluorescence staining is shown of animals receiving BM only, BM + WT splenocytes (cGvHD), or BM + CD146-KO splenocytes (20× magnification). Automated quantification of macrophages relative to cellular infiltrate was performed to ensure reproducible analysis and is summarized in terms of frequencies (mean ± SEM). n = 3 mice per group, BM only n = 2. (C) CD146-KO does not impact T-B cross talk within lymphoid organ. GC B cells (CD19⁺GL7⁺Fas^hi) and TFH (CD4⁺CXCR5⁺PD1^hiFoxP3^–) were analyzed by flow cytometry after spleen digestion at day 56 after transplant in animals receiving BM only, BM + WT splenocytes, or BM + CD146-KO splenocytes. n =3–7 mice per group. Comparisons in A–C were analyzed using the Wilcoxon rank-sum test