PT  - JOURNAL ARTICLE
AU  - Dawson, Nicholas A.J.
AU  - Rosado-Sánchez, Isaac
AU  - Novakovsky, German E.
AU  - Fung, Vivian C.W.
AU  - Huang, Qing
AU  - McIver, Emma
AU  - Sun, Grace
AU  - Gillies, Jana
AU  - Speck, Madeleine
AU  - Orban, Paul C.
AU  - Mojibian, Majid
AU  - Levings, Megan K
TI  - Functional effects of chimeric antigen receptor co-receptor signaling domains in human Tregs
AID  - 10.1101/749721
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 749721
4099  - http://biorxiv.org/content/early/2019/08/29/749721.short
4100  - http://biorxiv.org/content/early/2019/08/29/749721.full
AB  - Antigen-specific regulatory T cells (Tregs) engineered with chimeric antigen receptor (CARs) are a potent immunosuppressive cellular therapy in multiple disease models. To date the majority of CAR Treg studies employed second generation CARs, encoding a CD28 or 4-1BB co-receptor signaling domain and CD3ζ, but it was not known if this CAR design was optimal for Tregs. Using an HLA-A2-specific CAR platform and human Tregs, we compared ten CARs with different co-receptor signaling domains and systematically tested their function. Tregs expressing a CAR encoding wild-type CD28 were markedly superior to all other CARs tested in an in vivo model of graft-versus-host disease. In vitro assays revealed stable expression of Helios and ability to suppress CD80 expression on DCs as key in vitro predictors of in vivo function. This comprehensive study of CAR signaling-domain variants in Tregs can be leveraged to optimize CAR design for use in antigen-specific Treg therapy.