Immunosuppressed patients after solid organ transplantation (SOT) are at high risk to develop malignancies. Post-transplant lymphoproliferative disease (PTLD) is one of the most severe complications after SOT and manifests in the lung in up to 20% of the cases. In PTLD, latent Epstein-Barr virus (EBV)-infected B lymphocytes undergo uncontrolled proliferation, becoming tumorigenic EBV-transformed B cells. Immunosuppression after SOT leads to a general decrease of T cell immune surveillance leading to a detrimental disease outcome. The main treatment option for PTLD are anti-viral agents, nevertheless PTLD often ends fatal.

Anti-viral adoptive T cell therapy represents a novel therapeutical approach, which has shown promising results among other indications also for PTLD. In our lab, we are confident in generating EBV-specific T cell products. However, to confirm the safety and efficacy of these EBV-specific T-cell products as a basis for clinical translation, we are in urgent need of a suitable test platform.

We had the unique chance to set up a novel, human co-culture platform of patient derived 3D lung organoids and patient derived EBV-transformed lymphoblastoid cells (LCLs) mimicking PTLD in the lung, as we have access to primary lung tissue and blood samples from the same patient. In order to generate this platform, we already implemented a co-culture of primary lung organoids and corresponding LCLs from the same patient. We have found a suitable co-culture medium and investigated LCL interaction and infiltration into the organoid. Further, we assess viral load by real-time PCR and viral protein staining. Patient-specific EBV-reactive T cell product manufacturing is already established in a GMP compatible manner using a semi-closed bioreactor system, and we are now integrating these cells into the PTLD platform for testing safety and efficacy of this product. Safety, specificity and potential off-target activity of the EBV-specific T cell product is assessed by live cell imaging monitoring apoptosis e.g. by annexin V staining and using cell trackers for T cells and LCLs. Efficacy is determined by evaluation of viral load and abundance of LCLs. This autologous, human-derived platform holds the potential to produce relevant and reproducible results, yields valuable preclinical data regarding functionality, safety and efficacy of human EBV-specific T cell products and will pave the way for EBV-specific T cell products into the clinic.