CD146 bound to LCK promotes T cell receptor signaling and antitumor immune responses in mice
Hongxia Duan, Lin Jing, Xiaoqing Jiang, Yanbin Ma, Daji Wang, Jianquan Xiang, Xuehui Chen, Zhenzhen Wu, Huiwen Yan, Junying Jia, Zheng Liu, Jing Feng, Mingzhao Zhu, Xiyun Yan
Hongxia Duan, Lin Jing, Xiaoqing Jiang, Yanbin Ma, Daji Wang, Jianquan Xiang, Xuehui Chen, Zhenzhen Wu, Huiwen Yan, Junying Jia, Zheng Liu, Jing Feng, Mingzhao Zhu, Xiyun Yan
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Research Article Cell biology Immunology

CD146 bound to LCK promotes T cell receptor signaling and antitumor immune responses in mice

Abstract

Initiation of T cell receptor (TCR) signaling involves the activation of the tyrosine kinase LCK; however, it is currently unclear how LCK is recruited and activated. Here, we have identified the membrane protein CD146 as an essential member of the TCR network for LCK activation. CD146 deficiency in T cells substantially impaired thymocyte development and peripheral activation, both of which depend on TCR signaling. CD146 was found to directly interact with the SH3 domain of coreceptor-free LCK via its cytoplasmic domain. Interestingly, we found CD146 to be present in both monomeric and dimeric forms in T cells, with the dimerized form increasing after TCR ligation. Increased dimerized CD146 recruited LCK and promoted LCK autophosphorylation. In tumor models, CD146 deficiency dramatically impaired the antitumor response of T cells. Together, our data reveal an LCK activation mechanism for TCR initiation. We also underscore a rational intervention based on CD146 for tumor immunotherapy.

Authors

Hongxia Duan, Lin Jing, Xiaoqing Jiang, Yanbin Ma, Daji Wang, Jianquan Xiang, Xuehui Chen, Zhenzhen Wu, Huiwen Yan, Junying Jia, Zheng Liu, Jing Feng, Mingzhao Zhu, Xiyun Yan

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Figure 5

CD146 deletion impairs the TCR-mediated response of T cells.

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CD146 deletion impairs the TCR-mediated response of T cells. (A) Left: C...
(A) Left: CD4 and CD8 expression on splenic cells. Right: Percentage of cell populations (n = 8). (B) Cell numbers of splenic CD4+ and CD8+ populations (n = 8). (C) Left: CD44 and CD62L expression on splenic CD4+ and CD8+ cells. Right: Percentage of naive T (CD62L+CD44–) and memory T cells (CD62L–CD44+) in the CD4+ or CD8+ population (n = 5). (D) Left: CD69 expression on naive CD4+ T cells left stimulated for 5 hours. Right: Quantification of CD69+ cells and quantification of CD69 MFI (n = 3). (E and F) IL-2+ or IFN-γ+ cells of splenic naive T cells after stimulation for 3 days in vitro (n = 5). (G) Left: CFSE dilution in splenic naive T cells stimulated for 4 days. Red, nonproliferated cells; pink, proliferating cells. Right: Division index (n = 6). (H) Left: Staining of CD4 and OVA-MHC-II tetramer on splenic CD4+ T cells left stimulated with OVA323–339 peptide for 72 hours. Right: Percentage of tetramer+ populations (n = 6). (I) Left: CD69 expression on naive CD4+ T cells from tamoxifen-treated mice left stimulated for 5 hours. Right: Percentages of CD69+ cells (n = 4). (J) Histogram and MFI of CD69 (n = 4). (K) Analysis of TNF-α, IFN-γ, and IL-2 in tamoxifen-treated splenic naive T cells after stimulation for 72 hours (representative of n = 3). Each symbol represents an individual mouse. One-way ANOVA (A–D and G), 2-tailed t test (H–J), or 2-way ANOVA with multiple-comparison test (F) was performed. Data are shown as the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001.