Trogocytosis between Non-Immune Cells for Cell Clearance, and among Immune-Related Cells for Modulating Immune Responses and Autoimmunity

Abstract

The term trogocytosis refers to a rapid bidirectional and active transfer of surface membrane fragment and associated proteins between cells. The trogocytosis requires cell-cell contact, and exhibits fast kinetics and the limited lifetime of the transferred molecules on the surface of the acceptor cells. The biological actions of trogocytosis include information exchange, cell clearance of unwanted tissues in embryonic development, immunoregulation, cancer surveillance/evasion, allogeneic cell survival and infectious pathogen killing or intercellular transmission. In the present review, we will extensively review all these aspects. In addition to its biological significance, aberrant trogocytosis in the immune system leading to autoimmunity and immune-mediated inflammatory diseases will also be discussed. Finally, the prospective investigations for further understanding the molecular basis of trogocytosis and its clinical applications will also be proposed.

The Role of Trogocytosis in the Modulation of Immune Cell Functions

“…In the past decade, trogocytosis (named from the ancient Greek trogo-, which means gnaw or nibble) has been attracting increasing attention in the vast fields of biology research, including immunology, microbiology, neurology, and developmental biology [1][2][3][4][5][6][7]. Trogocytosis is an active process, in which one cell rapidly acquires the fraction of another cell in a cell contact-dependent manner [8] (Figure 1).…”

Shaping of T Cell Functions by Trogocytosis

“…Further, trogocytosis is used by amoebae to kill host cells [ 12 , 13 ], indicating that this biological phenomenon is widely conserved throughout eukaryotes. Recent findings of trogocytosis in microbes [ 14 ], mammalian neuronal networks [ 15 , 16 ], and non-T cell immune cell interactions [ 2 , 17 , 18 ] have been well summarized by others previously and also in this issue. Thus, here we mainly focus on T cell trogocytosis and related diseases.…”

“…Specifically, several studies have utilized the ability of CD8 + T cells to acquire antigen peptide-MHCI complexes in order to detect antigen-specific T cells in peripheral blood mononuclear cells (PBMCs) from patients infected with human T-cell lymphotropic virus type I (HTLV-1) or lymphocytic choriomeningitis virus (LCMV). Tomaru et al first successfully identified T cell populations that specifically recognize the HTLV-I Tax (11)(12)(13)(14)(15)(16)(17)(18)(19) peptide presented on HLA-A*201 [131]. In this study, the authors established Hmy2.CIR cells, an HLA-A and HLA-B locus-defective immortalized B cell line, transduced with HLA-A*201 fused with GFP.…”

Trogocytosis in innate immunity to cancer is an intimate relationship with unexpected outcomes

“…The molecules transferred via trogocytosis are functional and influence the response of the receiving cell, thus implying consequences for the modulation of immune responses. Therefore, trogocytosis represents an important process for cell-cell communication, immune regulation, and response to pathogens and cancerous cells ( Li et al., 2021 ; Miyake and Karasuyama, 2021 ).…”

“…In addition, as we will discuss, innate immune cells may employ prolonged trogocytosis to induce tumor cell death ( Matlung et al., 2018 ; Velmurugan et al., 2016 ). The contact between different types of immune cells via trogocytosis is a phenomenon also occurring in the TME as a strategy to modulate the function of immune cells, thus indirectly affecting cancer progression ( Li et al., 2021 ). In this respect, trogocytosis can be regarded as a double-edge sword in cancer immunity involved in both activation and repression pathways of immune responses to cancer.…”