Introduction: Xenogeneic lung transplantation with genetically engineered pig lungs is an emerging potential solution to the global shortage of human donor organs. Immune rejection and ischemia-reperfusion injury (IRI) are major barriers to clinical success. IRI induces oxidative stress and innate immunity activation by damage-associated molecular patterns (DAMPs), potentially furthered by species-specific immune differences. The objective here is to Understand how porcine immune components such as, cytokines (IL3 and MCSF ) and surfactant protein D (SP-D), affect human monocytes as it is pivotal for implementing potential immunomodulatory therapies.
Methods: In phase 1 compatibility of porcine IL-3 and M-CSF for human monocyte survival and differentiation to that of human IL3 and MCSF. Human Monocytes were cultured and differentiated to macrophages over 14 days using Human/Pig or Mixed IL-3 and M-CSF and viability was measured through live –dead assays.Phenotypic shifts were analysed by investigating Surface markers (CD11b, CD80, CD206) via flow cytometry. Phase 2 was conducted to analyze the effect of porcine SP-D on human monocyte polarization and morphology. Human Monocytes were treated with increasing doses of pig SP-D and polarization patterns were analyzed by flow cytometry on day 2,8 and 14. Immunostaining of surface markers cd80,cd206 and CD11b was used to visualize phenotypic differences between human or pig SP-D treated human monocytes to get a preliminary understanding of the protein`s immunomodulatory effects. Dose-response experiments are ongoing to determine the most suitable concentration for comparative analysis
Results and Conclusion: Preliminary data suggests F Porcine IL-3 combined with human MCSF /Pig MCSF is suppressive to human monocyte viability, perhaps secondary to receptor incompatibility, while porcine M-CSF when combined with human IL3 promote survival but is unable to induce effective differentiation. Additionally, porcine SP-D stimulates a pro-inflammatory phenotype(CD80) in human monocytes that is contrary to the usually immunoregulatory role of the human homolog. These findings suggest important species-to-species differences that potentially may contribute to graft rejection. It will be crucial to delineate and prevent such differences so that specific immunomodulatory strategies can be developed to further graft acceptance and advance the therapeutic potential of xenogeneic lung transplantation.