Transient mTOR inhibition rescues 4-1BB CAR-Tregs from tonic signal-induced dysfunction

Baptiste Lamarthée (1) , Armance Marchal (1) , Soëli Charbonnier (1) , Tifanie Blein (1) , Juliette Leon (2) , Emmanuel Martin (1) , Lucas Rabaux (1) , Katrin Vogt (3) , Matthias Titeux (1) , Marianne Delville (1, 4) , Hélène Vinçon (1) , Emmanuelle Six (1) , Nicolas Pallet (5) , David Michonneau (6) , Dany Anglicheau (7, 4) , Christophe Legendre (4, 8) , Jean-Luc Taupin (8, 9) , Ivan Nemazanyy (10) , Birgit Sawitzki (3) , Sylvain Latour (1) , Marina Cavazzana (1, 4) , Isabelle André (1) , Julien Zuber (1, 4)

1 Imagine - U1163 - Imagine - Institut des maladies génétiques (IHU)
2 HMS - Harvard Medical School [Boston]
3 Charité - UniversitätsMedizin = Charité - University Hospital [Berlin]
4 Hôpital Necker - Enfants Malades [AP-HP]
5 CRC (UMR_S_1138 / U1138) - Centre de Recherche des Cordeliers
6 HIPI (UMR_S_976 / U976) - Immunologie humaine, physiopathologie & immunothérapie
7 INEM - UM 111 (UMR 8253 / U1151) - Institut Necker Enfants-Malades
8 UPCité - Université Paris Cité
9 AP-HP - Hopital Saint-Louis [AP-HP]
10 UAR 3633 / US24 - Structure Fédérative de Recherche Necker

Abstract The use of chimeric antigen receptor (CAR)-engineered regulatory T cells (Tregs) has emerged as a promising strategy to promote immune tolerance. However, in conventional T cells (Tconvs), CAR expression is often associated with tonic signaling, which can induce CAR-T cell dysfunction. The extent and effects of CAR tonic signaling vary greatly according to the expression intensity and intrinsic properties of the CAR. Here, we show that the 4-1BB CSD-associated tonic signal yields a more dramatic effect in CAR-Tregs than in CAR-Tconvs with respect to activation and proliferation. Compared to CD28 CAR-Tregs, 4-1BB CAR-Tregs exhibit decreased lineage stability and reduced in vivo suppressive capacities. Transient exposure of 4-1BB CAR-Tregs to a Treg stabilizing cocktail, including an mTOR inhibitor and vitamin C, during ex vivo expansion sharply improves their in vivo function and expansion after adoptive transfer. This study demonstrates that the negative effects of 4-1BB tonic signaling in Tregs can be mitigated by transient mTOR inhibition.

Domaines: Sciences du Vivant [q-bio]

Baptiste Lamarthée, Armance Marchal, Soëli Charbonnier, Tifanie Blein, Juliette Leon, et al.. Transient mTOR inhibition rescues 4-1BB CAR-Tregs from tonic signal-induced dysfunction. Nature Communications, 2021, 12 (1), ⟨10.1038/s41467-021-26844-1⟩. ⟨hal-03442950⟩