The Multiple Roles of Trogocytosis in Immunity, the Nervous System, and Development

Abstract

Trogocytosis is a general biological process that involves one cell physically taking small parts of the membrane and other components from another cell. In trogocytosis, one cell seems to take little “bites” from another cell resulting in multiple outcomes from these cell-cell interactions. Trogocytosis was first described in protozoan parasites, which by taking pieces of host cells, kill them and cause tissue damage. Now, it is known that this process is also performed by cells of the immune system with important consequences such as cell communication and activation, elimination of microbial pathogens, and even control of cancer cells. More recently, trogocytosis has also been reported to occur in cells of the central nervous system and in various cells during development. Some of the molecules involved in phagocytosis also participate in trogocytosis. However, the molecular mechanisms that regulate trogocytosis are still a mystery. Elucidating these mechanisms is becoming a research area of much interest. For example, why neutrophils can engage trogocytosis to kill Trichomonas vaginalis parasites, but neutrophils use phagocytosis to eliminate already death parasites? Thus, trogocytosis is a significant process in normal physiology that multiple cells from different organisms use in various scenarios of health and disease. In this review, we present the basic principles known on the process of trogocytosis and discuss the importance in this process to host-pathogen interactions and to normal functions in the immune and nervous systems.

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

“…During TCR/MHC interaction between T cells and APCs, the IS directs the actin network close to the clusters of TCR complexes ( Dopfer et al., 2011 ) via the PI3K and two small GTPases RhoG and RRas ( Uribe-Querol and Rosales, 2021 ). As Rho compounds are well recognized for their key role in F-actin contraction and polymerization ( Lou et al., 2019 ), it is likely that Rho molecules are recruited near the clustering TCR molecules and then bind actin filaments, triggering synchronized contraction that results in an engulfment-like rearrangement of the membrane.…”

NK Cells Acquire CCR5 and CXCR4 by Trogocytosis in People Living with HIV-1

“…Why are certain plasma membrane molecules trogocytosed and not others? This is unknown, and it is probably related to the unknowledge of the mechanism(s) of trogocytosis [ 5 , 31 ]. Of note, the co-trogocytosis of CD4 with CCR5 or CXCR4 could have resulted in the HIV-1 infectibility of NK cells in the same way as trans-synaptic acquisition of CD21 by NK cells allowed EBV binding [ 32 ].…”

Neutrophil trogocytosis during their trans-endothelial migration: role of extracellular CIRP

“…Neutrophil trogocytosis were seen in different modes including cancer cell killing with coated antibody, parasite removal, excess sperm removal, and cellular communication with other immune cells (Uribe-Querol and Rosales 2021 ). While several studies have shown trogocytosis between neutrophils and immune cells, very little is known about neutrophil trogocytosis with non-immune cells such as endothelial cells.…”

“…A newly-reported function of neutrophils is trogocytosis or membrane transfer with neighboring cells, to modulate innate and adaptive immune responses (Kruger et al 2015 ; Tsai 2021 ). Trogocytosis has been observed in many organisms including protozoa, nematode, and many different cell types in higher organisms (Uribe-Querol and Rosales 2021 ). There are different modes of trogocytosis observed including cell killing or cell-to-cell communication (Miyake and Karasuyama 2021 ).…”