Complementarity-determining region clustering may cause CAR-T cell dysfunction.

Sarén T, Saronio G, Marti Torrell P, Zhu X, Thelander J, Andersson Y, Hofström C, Nestor M, Dimberg A, Persson H, Ramachandran M, Yu D, Essand M

Nat Commun 14 (1) 4732 [2023-08-10; online 2023-08-10]

Chimeric antigen receptor (CAR)-T cell therapy is rapidly advancing as cancer treatment, however, designing an optimal CAR remains challenging. A single-chain variable fragment (scFv) is generally used as CAR targeting moiety, wherein the complementarity-determining regions (CDRs) define its specificity. We report here that the CDR loops can cause CAR clustering, leading to antigen-independent tonic signalling and subsequent CAR-T cell dysfunction. We show via CARs incorporating scFvs with identical framework and varying CDR sequences that CARs may cluster on the T cell surface, which leads to antigen-independent CAR-T cell activation, characterized by increased cell size and interferon (IFN)-γ secretion. This results in CAR-T cell exhaustion, activation-induced cell death and reduced responsiveness to target-antigen-expressing tumour cells. CDR mutagenesis confirms that the CAR-clustering is mediated by CDR-loops. In summary, antigen-independent tonic signalling can be induced by CDR-mediated CAR clustering, which could not be predicted from the scFv sequences, but could be tested for by evaluating the activity of unstimulated CAR-T cells.

Bioinformatics Support for Computational Resources [Service]

Drug Discovery and Development (DDD) [Collaborative]

Global Proteomics and Proteogenomics [Service]

PubMed 37563127

DOI 10.1038/s41467-023-40303-z

Crossref 10.1038/s41467-023-40303-z

pmc: PMC10415375
pii: 10.1038/s41467-023-40303-z

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