Regeneration of a Sustained Antiviral Response in Transplant Recipients by Tacrolimus Resistant Antiviral T-cell Products

Abstract Text: Viral complications are major risk factors for immunocompromised patients after solid organ transplantation (SOT). SOT patients depend on lifelong immunosuppression, dampening endogenous T-cell response against viral infections. In particular, reactivation of cytomegalovirus (CMV), Epstein-Barr virus (EBV) and Influenza A virus (IAV) cause severe threads to SOT patients. EBV for one elicits posttransplant lymphoproliferative disease (PTLD), leading to mortality rates of up to 25% in SOT patients. Furthermore, respiratory viruses as influenza-A virus (IAV) can cause severe destruction of the respiratory tract, while vaccination responses in those patients remain insufficient.
To regenerate a broad, protective antiviral T-cell response in immunocompromised patients and prevent viral complications, we have established a GMP-compliant manufacturing for tacrolimus-resistant CMV-, EBV- and IAV-specific T-cell products (TCPs) ready-to-use for adoptive T-cell therapy. After specific peptide-driven enrichment of effector T-cells, tacrolimus-resistance is induced through a vector-free CRISPR-Cas9-based knockout of FKBP12, the adaptor protein for tacrolimus. With that, maintenance of effector cytokine production and target specific killing capacity of TCPs is secured, while preventing anti-allogenic rejection of the graft by immunosuppression. The safety of tacrolimus-resistant TCPs is verified using in-depth CITE-sequencing and mass spectrometry. Additionally, efficacy of e.g. IAV-specific TCPs is assessed using a human-based native infection model. Currently, patient data from immunocompromised individuals is acquired. Developed single-virus-specific T-cells further lay the basis for FKBP12KO multivirus-specific TCPs addressing spectrum combinatorial treatment with an equally constituted antigen-specific T-cell pool. These next generation ATMPs have potential long-term regeneration of pathogenic responses in immunocompromised patients and help in the fight against viral threads.