The Role of Trogocytosis in the Modulation of Immune Cell Functions

Abstract

Trogocytosis is an active process, in which one cell extracts the cell fragment from another cell, leading to the transfer of cell surface molecules, together with membrane fragments. Recent reports have revealed that trogocytosis can modulate various biological responses, including adaptive and innate immune responses and homeostatic responses. Trogocytosis is evolutionally conserved from protozoan parasites to eukaryotic cells. In some cases, trogocytosis results in cell death, which is utilized as a mechanism for antibody-dependent cytotoxicity (ADCC). In other cases, trogocytosis-mediated intercellular protein transfer leads to both the acquisition of novel functions in recipient cells and the loss of cellular functions in donor cells. Trogocytosis in immune cells is typically mediated by receptor–ligand interactions, including TCR–MHC interactions and Fcγ receptor-antibody-bound molecule interactions. Additionally, trogocytosis mediates the transfer of MHC molecules to various immune and non-immune cells, which confers antigen-presenting activity on non-professional antigen-presenting cells. In this review, we summarize the recent advances in our understanding of the role of trogocytosis in immune modulation.

Gnawing Between Cells and Cells in the Immune System: Friend or Foe? A Review of Trogocytosis

“…In general, the typical manner for antigen presentation is that professional APCs (such as DCs) process the protein antigens into pMHCs (antigenic peptide-MHC complexes) and then present them to T cells. Some researches revealed a new antigen presentation pathway in which APCs and non-APCs directly obtained preformed pMHCs on the surface of target cells by trogocytosis and activated T cells without further processing (7,10,14,19). Subsequently, the trogocytosis of MHCs occurs not only in T cell-APCs but also in T cell-endothelial cells, APC-APCs, APC-NK cells, tumor cell-T cells, and NK cells (43)(44)(45)(46)(47).…”

“…Trogocytosis was generally a biological process between cells mediated by the formation of the immunological synapse or by the contact of ligands (adhesion molecules, chemokines, antibodies, complements, etc.) and receptors (14,22,(90)(91)(92)(93) with involvement of actin and PI3K (Phosphoinositide 3-kinase) (22,52,94). In specific cell types, TC21, RhoG, Src, Syk intracellular calcium and myosin lightchain kinase also played an important role (22,52,94).…”

“…Trogocytosis does not always lead to the death of target cells. The interaction is relatively mild and tends to take up material and exchange information under physiological conditions, while it is often strong and usually ends in the death of target cells under pathological conditions (14,20,33). The existence of trogocytosis has shaken the traditional notion that cells can only perform their inherent functions or that a gene must be transcribed to use its protein product.…”

NK cells acquire CCR5 and CXCR4 by trogocytosis in people living with HIV-1

“…During steady states as well as in acute viral infections, NK cells are thought to constantly interact with their neighboring cells within the tissue microenvironment or in circulation via a wide range of receptors and adhesion molecules expressed on their surface [1][2][3]. As a consequence, these close-range contacts between NK cells and their targets often results in passive or active transferring of membrane patches and other surface molecules from the target cells into the effector (NK) cells [4], a process called trogocytosis [5,6]. Trogocytosis is a process firstly described and widely observed in other lymphocytes including B and T cells [5].…”

“…As a consequence, these close-range contacts between NK cells and their targets often results in passive or active transferring of membrane patches and other surface molecules from the target cells into the effector (NK) cells [4], a process called trogocytosis [5,6]. Trogocytosis is a process firstly described and widely observed in other lymphocytes including B and T cells [5]. The potential trogocytosis between HIV-infected cells and NK cells, as well as its physiological consequence, has not been described, and very few is known regarding other immune cells [6,7].…”