1
|
Straub A, Grassmann S, Jarosch S, Richter L, Hilgendorf P, Hammel M, Wagner KI, Buchholz VR, Schober K, Busch DH. Recruitment of epitope-specific T cell clones with a low-avidity threshold supports efficacy against mutational escape upon re-infection. Immunity 2023:S1074-7613(23)00179-6. [PMID: 37164014 DOI: 10.1016/j.immuni.2023.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/01/2023] [Accepted: 04/13/2023] [Indexed: 05/12/2023]
Abstract
Repetitive pathogen exposure leads to the dominant outgrowth of T cell clones with high T cell receptor (TCR) affinity to the relevant pathogen-associated antigens. However, low-affinity clones are also known to expand and form immunological memory. While these low-affinity clones contribute less immunity to the original pathogen, their role in protection against pathogens harboring immune escape mutations remains unclear. Based on identification of the TCR repertoire and functionality landscape of naive epitope-specific CD8+ T cells, we reconstructed defined repertoires that could be followed as polyclonal populations during immune responses in vivo. We found that selective clonal expansion is governed by clear TCR avidity thresholds. Simultaneously, initial recruitment of broad TCR repertoires provided a polyclonal niche from which flexible secondary responses to mutant epitopes could be recalled. Elucidating how T cell responses develop "from scratch" is informative for the development of enhanced immunotherapies and vaccines.
Collapse
Affiliation(s)
- Adrian Straub
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany
| | - Simon Grassmann
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany; The Joseph Sun Lab, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Sebastian Jarosch
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany
| | - Lena Richter
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany
| | - Philipp Hilgendorf
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany; Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Monika Hammel
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany
| | - Karolin I Wagner
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany
| | - Veit R Buchholz
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany
| | - Kilian Schober
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany; Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany; Medical Immunology Campus Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Schlossplatz 1, 91054 Erlangen, Germany.
| | - Dirk H Busch
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München (TUM), Munich, Germany; Partner site Munich, German Center for Infection Research (DZIF), Munich, Germany.
| |
Collapse
|
2
|
Efficient killing of tumor cells by CAR-T cells demands engagement of a larger number of CARs as opposed to TCRs. J Biol Chem 2021; 297:101033. [PMID: 34371020 PMCID: PMC8452787 DOI: 10.1016/j.jbc.2021.101033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 01/21/2023] Open
Abstract
Although CAR T cells are widely used to treat cancer, efficiency of CAR-T cell cytolytic responses has not been carefully examined. We engineered CAR specific for HMW-MAA (high molecular weight melanoma-associated antigen) and evaluated potency of CD8+ CAR-T cells to release cytolytic granules and to kill tissue-derived melanoma cells, which express different levels of HMW-MAA. CAR T cells efficiently killed melanoma cells expressing high level of HMW-MAA, but not melanoma cells with lower levels of HMW-MAA. The same melanoma cells presenting significantly lower level of stimulatory peptide-MHC ligand were readily lysed by T cells transduced with genes encoding α,β-TCR specific for the peptide-MHC ligand. The data suggest that higher level of targeted molecules is required to engage a larger number of CARs than TCRs to induce efficient cytolytic granule release and destruction of melanoma cells. Understanding the difference in molecular mechanisms controlling activation thresholds of CAR- versus TCR-mediated responses will contribute to improving efficiency of CAR T cells required to eliminate solid tumors presenting low levels of targeted molecules.
Collapse
|