Acellular normothermic spleen perfusion resolves transcriptional and non-transcriptional mechanisms of steroid immunosuppression

The limiting step in immune-active drug development is increasingly not candidate generation but testing whether a candidate therapy is effective in a system that preserves tissue architecture, vascular exposure, multicellular interaction, and repeated pharmacodynamic sampling without patient exposure. We developed an acellular normothermic machine-perfusion platform for intact porcine spleen designed as a translational immune-organ assay. Across independent acellular perfusions, the circuit maintained physiologic parameters, preserved red- and white-pulp histology, and yielded viable effluent cells suitable for serial flow cytometry and multiomics. High-dose methylprednisolone was used as a clinically familiar perturbation to determine whether the platform could resolve steroid immunosuppression at mechanistically distinct levels. Effluent RNA-seq identified canonical glucocorticoid-responsive transcriptional programs, including DUSP1, FKBP5, PER1, DDIT4, SGK1, KLF9, ANXA1, NF-{kappa}B feedback regulators, and JAK/STAT suppressor pathways. SOCS3 was a prominent early signal in the perfusion transcriptome and was validated orthogonally at the protein level in prednisone-treated, CD3/CD28-activated primary murine splenocytes, strengthening its role as a candidate pharmacodynamic marker. In parallel, data independent acquisition (DIA) proteomics of effluent cell pellets nominated a non-transcriptional protein-level response: a Sus scrofa LGALS13-annotated, CLC/Galectin-10-like galectin detected despite absence of the corresponding effluent-cell transcript. Because this porcine LGALS13-annotated protein group is treated here as an orthologous CLC/Galectin-10-like signal rather than as canonical human placental Galectin-13/PP13, we tested recombinant human Galectin-10 in vitro. Human Galectin-10 induced marked apoptosis of CD3/CD28-stimulated Jurkat cells, prioritizing this axis for future mechanistic testing without proving causality in the perfused spleen. These data establish acellular spleen perfusion as a serial multiomic platform for translational immunopharmacology and motivate deployment with otherwise-discarded human donor spleens. One sentence summaryAn acellular intact-spleen perfusion platform enables serial cellular, transcriptomic, proteomic, and functional pharmacodynamic sampling that identifies steroid-responsive transcriptional programs, validates SOCS3 protein induction, and nominates a CLC/Galectin-10-like non-transcriptional immunosuppressive axis for translation to discarded human donor spleens.