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Abstract
As the targets of chimeric antigen receptor (CAR)-T cells expand to a variety of cancers, autoimmune diseases, viral infections, and fibrosis, there is an increasing demand for identifying new antigens and designing new CARs that can be effectively activated. However, the rational selection of antigens and the design of CARs are limited by a lack of knowledge regarding the molecular mechanism by which CARs are activated by antigens. Here, we present data supporting a "size exclusion" model explaining how antigen signals are transmitted across the plasma membrane to activate the intracellular domains of CARs. In this model, antigen engagement with CAR results in a narrow intermembrane space that physically excludes CD45, a bulky phosphatase, out of the CAR zone, thus favoring CAR phosphorylation by kinases, which further triggers downstream pathways leading to T cell activation. Aligned with this model, increasing the size of CAR extracellular domains diminished CAR-T activation both in vitro and in a mouse lymphoma model; membrane-proximal epitopes activated CAR-Ts better than membrane-distal epitopes. Moreover, increasing the size of CD45 by antibody conjugation enhanced the activation of CARs that recognize membrane-distal epitopes. Consistently, CAR-Ts expressing CD45RABC, the larger isoform, were activated to a higher level than those expressing a smaller isoform CD45RO. Together, our work revealed that CAR-T activation depends on the size difference between the CAR-antigen pair and CD45; the size of CAR, antigen, and CD45 can thus be targets for tuning CAR-T activation.
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Affiliation(s)
- Qian Xiao
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA
- Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Xinyan Zhang
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Liqun Tu
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA
| | - Jian Cao
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA
- Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Christian S. Hinrichs
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA
- Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Xiaolei Su
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA
- Yale Cancer Center, Yale University, New Haven, CT, 06520, USA
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Wang T, Shen C, Li H, Chen L, Liu S, Qi J. High resolution HLA-DRB1 analysis and shared molecular amino acid signature of DRβ1 molecules in Occult hepatitis B infection. BMC Immunol 2022; 23:22. [PMID: 35468727 PMCID: PMC9040378 DOI: 10.1186/s12865-022-00496-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/14/2022] [Indexed: 11/10/2022] Open
Abstract
AIM To investigate the association of human leukocyte antigen (HLA)-DRB1 alleles and the variations of polymorphic amino acid changes in DRβ1 chain in Shaanxi Han population with Occult hepatitis B infection (OBI). METHODS High-resolution HLA-DRB1 genotyping was performed in 107 OBI carriers and 280 normal controls. Sequence information was used to assign which amino acids were encoded at all polymorphic positions. Three-dimensional modeling was performed to explore the effect of the key residues on the HLA-DRB1 molecule. RESULTS Strong susceptible association for allele DRB1*07:01 was observed in OBI carriers. The amino acid variation at HLA-DRβ1 molecule revealed susceptible associations for residues Gln4β, Val57β(P9), Ser60β(P9) and Val78β(P4), the amino acids Arg4β, Asp57β(P9), Tyr60β(P9) and Tyr78β(P4) showed protective associations. CONCLUSION Alleles DRB1*07:01 showed strong susceptible associations in OBI carriers. The amino acid variations in DRβ molecules revealed significant molecular markers for susceptibility and protection from OBI in Shaanxi Han population.
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Affiliation(s)
- Tianju Wang
- HLA Typing Laboratory, Blood Center of the Shaanxi Province, Institute of Xi'an Blood Bank, 407# Zhuque Ave, Xi'an, Shaanxi Province, 710061, People's Republic of China
| | - Chunmei Shen
- HLA Typing Laboratory, Blood Center of the Shaanxi Province, Institute of Xi'an Blood Bank, 407# Zhuque Ave, Xi'an, Shaanxi Province, 710061, People's Republic of China.,Key Laboratory of Environment and Gene Related to Diseases, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, People's Republic of China
| | - Hengxin Li
- HLA Typing Laboratory, Blood Center of the Shaanxi Province, Institute of Xi'an Blood Bank, 407# Zhuque Ave, Xi'an, Shaanxi Province, 710061, People's Republic of China
| | - Liping Chen
- HLA Typing Laboratory, Blood Center of the Shaanxi Province, Institute of Xi'an Blood Bank, 407# Zhuque Ave, Xi'an, Shaanxi Province, 710061, People's Republic of China
| | - Sheng Liu
- HLA Typing Laboratory, Blood Center of the Shaanxi Province, Institute of Xi'an Blood Bank, 407# Zhuque Ave, Xi'an, Shaanxi Province, 710061, People's Republic of China
| | - Jun Qi
- HLA Typing Laboratory, Blood Center of the Shaanxi Province, Institute of Xi'an Blood Bank, 407# Zhuque Ave, Xi'an, Shaanxi Province, 710061, People's Republic of China.
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