Analysis of tumor infiltrating CD4+ and CD8+ CDR3 sequences reveals shared features putatively associated to the anti-tumor immune response

Abstract

T cell receptor; Breast cancer; Tumor-infiltrating lymphocytes

Receptor de células T; Cáncer de mama; Linfocitos infiltrantes de tumores

Receptor de cèl·lules T; Càncer de mama; Limfòcits infiltrants de tumors

Introduction: Tumor-infiltrating lymphocytes (TILs) have predictive and prognostic value in breast cancer (BC) and exert a protective function against tumor growth, indicating that it is susceptible to treatment using adoptive cell transfer of TILs or T cell receptor (TCR)-based therapies. TCR can be used to identify naturally tumor-reactive T cells, but little is known about the differences in the TCR repertoires of CD4+ and CD8+ TILs. Methods: TCR high-throughput sequencing was performed using TILs derived from the initial cultures of 11 BC biopsies and expanded and sorted CD4+ and CD8+ TILs as well as using PBMCs from healthy donors expanded and sorted using the same methodology. Results: Physicochemical TCR differences between T cell subsets were observed, as CD4+ TILs presented larger N(D)Nnt TRB sequences and with a higher usage of positively charged residues, although only the latest was also observed in peripheral T cells from healthy individuals. Moreover, in CD4+ TILs, a more restricted TCR repertoire with a higher abundance of similar sequences containing certain amino acid motifs was observed. Discussion: Some differences between CD4+ and CD8+ TCRs were intrinsic to T cell subsets as can also be observed in peripheral T cells from healthy individuals, while other were only found in TILs samples and therefore may be tumor-driven. Notably, the higher similarity among CD4+ TCRs suggests a higher TCR promiscuity in this subset.

This project was funded by Roche Farma, S.A. grant SP181123001, and by the Contigo Contra el Cáncer de la Mujer Foundation (#BREASTILs Project, “Functional Study of TILs from breast cancer patients: an approach to personalized medicine”). Roche Farma, S.A. funder was not involved in the study design, collection, analysis, interpretation of data, writing of this article, or decision to submit it for publication.