Programmpunkt

12:20

Titel: Peptide-Specific CAR-T Cells and TRUCKs with Inducible IL-12 Expression Control Epstein-Barr Virus-Associated Lymphoproliferation
ID: VS-5-3
Art: Abstractvortrag
Redezeit: 5 + 5 min
Session:
Sektion Stammzelltransplantation und Zelltherapie
VS-5

Referent: Anna Christina Dragon (Hannover)


Abstract - Text

Offenlegung Interessenkonflikt:

The authors declare that there is no conflict of interest.

Methods

To specifically target EBV-infected B cells, we designed a novel peptide-selective chimeric antigen receptor (CAR) based on the antibody TÜ165. In order to attract additional immune cells, we moreover developed TÜ165-based T cells redirected for universal cytokine-mediated killing (TRUCKs), which induced IL-12 release upon target contact. For that, constitutive TÜ165 CAR expression and inducible cytokine expression were encoded in an "all-in-one" lentiviral vector. Functionality of the engineered T cells was assessed in co-cultures with EBNA-3C-peptide-loaded, HLA-B*35-expressing K562 cells and EBV-infected B cells as PTLD model. TRUCKs were further tested for their chemoattractive and activating potential towards monocytes and NK cells.

Results

After co-cultivation with EBV target cells, TÜ165 CAR-Ts and TRUCKs showed an increased activation marker expression (CD137, CD25) and release of pro-inflammatory cytokines (IFN-γ, TNF-α). Moreover, TÜ165 CAR-Ts and TRUCKs released apoptosis-inducing mediators (granzyme B, perforin) and were capable to specifically lyse EBV-positive target cells. Live cell imaging revealed a specific attraction of TÜ165 CAR-Ts around the target cells. Of note, TÜ165 TRUCKs with inducible IL-12 showed highly improved effector functions. The target-induced release of IL-12 additionally led to recruitment of monocyte and NK cell lines as well as to an increased killing capacity of NK-92 cells.

Background

Immunosuppressive therapy or T-cell depletion in transplant patients can cause uncontrolled growth of Epstein-Barr virus (EBV)-infected B cells resulting in post-transplant lymphoproliferative disease (PTLD). Current treatment options do not distinguish between healthy and malignant B cells and are thereby often limited by severe side-effects in the already immunocompromised patients. The antibody TÜ165 recognizes an Epstein-Barr nuclear antigen (EBNA)-3C-derived peptide in HLA-B*35 context.

Conclusion

Our results demonstrate that TÜ165 CAR-Ts recognize EBV peptide/HLA complexes and thereby allow for recognizing an intracellular EBV target. TÜ165 TRUCKs recruited additional immune cells which are generally missing in proximity of lymphoproliferation in immunocompromised PTLD patients. This suggests a new and promising strategy to specifically target EBV-infected cells while sparing and mobilizing healthy immune cells and thereby enable control of EBV-associated lymphoproliferation.