Introduction

AUTHOR=Na Kwangmin , Lee Seul , Kim Dong Kwon , Kim Young Seob , Hwang Joon Yeon , Kang Seong-san , Baek Sujeong , Lee Chai Young , Yang Seung Min , Han Yu Jin , Kim Mi hyun , Han Heekyung , Kim Youngtaek , Kim Jae Hwan , Jeon Seunghyun , Byeon Youngseon , Lee Jii Bum , Lim Sun Min , Hong Min Hee , Pyo Kyoung-Ho , Cho Byoung Chul TITLE=CD81 and CD82 expressing tumor-infiltrating lymphocytes in the NSCLC tumor microenvironment play a crucial role in T-cell activation and cytokine production JOURNAL=Frontiers in Immunology VOLUME=15 YEAR=2024 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1336246 DOI=10.3389/fimmu.2024.1336246 ISSN=1664-3224 ABSTRACT=Introduction

To understand the immune system within the tumor microenvironment (TME) of non-small cell lung cancer (NSCLC), it is crucial to elucidate the characteristics of molecules associated with T cell activation.

Methods

We conducted an in-depth analysis using single-cell RNA sequencing data obtained from tissue samples of 19 NSCLC patients. T cells were classified based on the Tumor Proportion Score (TPS) within the tumor region, and molecular markers associated with activation and exhaustion were analyzed in T cells from high TPS areas.

Results

Notably, tetraspanins CD81 and CD82, belonging to the tetraspanin protein family, were found to be expressed in activated T cells, particularly in cytotoxic T cells. These tetraspanins showed strong correlations with activation and exhaustion markers. In vitro experiments confirmed increased expression of CD81 and CD82 in IL-2-stimulated T cells. T cells were categorized into CD81^highCD82^high and CD81^lowCD82^low groups based on their expression levels, with CD81^highCD82^high T cells exhibiting elevated activation markers such as CD25 and CD69 compared to CD81^lowCD82^low T cells. This trend was consistent across CD3⁺, CD8⁺, and CD4⁺ T cell subsets. Moreover, CD81^highCD82^high T cells, when stimulated with anti-CD3, demonstrated enhanced secretion of cytokines such as IFN-γ, TNF-α, and IL-2, along with an increase in the proportion of memory T cells. Bulk RNA sequencing results after sorting CD81^highCD82^high and CD81^lowCD82^low T cells consistently supported the roles of CD81 and CD82. Experiments with overexpressed CD81 and CD82 showed increased cytotoxicity against target cells.

Discussion

These findings highlight the multifaceted roles of CD81 and CD82 in T cell activation, cytokine production, memory subset accumulation, and target cell cytolysis. Therefore, these findings suggest the potential of CD81 and CD82 as promising candidates for co-stimulatory molecules in immune therapeutic strategies for cancer treatment within the intricate TME.