Table 1.

Multiple cells perform trogocytosis.

Trogocytic cell	Target cell	Mechanism involved in trogocytosis	Ref.
Trogocytosis is used by amoebas for cell killing
Naegleria fowleri	Neurons	Amoebas destroy mammalian cells by taking (nibbling) little pieces off them.	[12, 99, 100]
Dictyostelium caveatum	Other Dictyostelium species	D. caveatum are able to eat amoebas larger than themselves by nibbling pieces of the cells until they are small enough to be ingested. D. caveatum amoebas have the capacity to ingest amoebae of other Dictyostelium species, but do not attack each other. Dictyostelium amoebae faced with starvation trigger a developmental program during which many cells aggregate and form fruiting bodies that consist of a ball of spores held aloft by a thin stalk.	[101] [102, 103]
Entamoeba histolytica	Live intestinal epithelial cells	Amoebas attach to host cell glycoproteins containing galactose (Gal) or N-acetyl-galactosamine (GalNAc) via their Gal/GalNAc lectin. Upon attachment, trogocytosis signaling involves PI-3K and EhC2PK, both of which promote actin polymerization. Cell damage induced by trogocytosis involves acidified lysosomes and cysteine proteinases. E. histolytica is susceptible to complement-mediated lysis, but during trogocytosis, amoebas can incorporate host cell membrane proteins, such as CD59, and become resistant to complement-mediated lysis.	[14, 97], [24, 25], [22, 27]
Cells of the immune system use trogocytosis for cell communication
B cells	Cells with cognate antigens	B cells form a close contact “synapse” with antigens on the membrane of a target cell. B cells then nibble on the target cell and acquire little pieces of antigen-containing membrane.	[6]
T cells B cells	Antigen-presenting cells (APC) and lymphocytes	Lymphocytes acquire antigen together with major histocompatibility complex (MHC) molecules. CD28 is important for initiating trogocytosis.	[10, 15, 33, 34]
NK cells	Dendritic cells	Acquisition of MHC class II molecules and costimulatory molecules such as CD80 and CD86. These MHC class II-dressed NK cells inhibited DC-induced CD4+ T cell responses.	[28, 35]
Plasmacytoid dendritic cells (pDC)	Cancer cells	Acquisition of intact MHC-antigen (Ag) complexes which could be efficiently recognized by tumor-specific CD8+ T lymphocytes.	[29]
Macrophages	Antibody-coated cells	Fc gamma receptor- (FcγR-) mediated trogocytosis removes antibodies “antibody shaving” from cells, allowing tumor cells to escape therapy.	[30, 36, 37, 47–49]
Neutrophil	Monocytes T and B cells	Acquisition of MHC class I and class II, the integrin LFA-1, and the chemokine receptor CXCR1. Trogocytosis activates survival and activation signals to enhance neutrophil functions. Signaling involves actin polymerization, clathrin activation, and Fc receptors.	[8, 98]
Neutrophil	Trichomonas vaginalis	Neutrophils surround and take “bites” of the parasite membrane.	[18]
Neutrophil	Sperm cells	Neutrophils took “bites” of sperm and quickly reduced their motility and viability.	[42]
Macrophage	Bacteria-infected macrophage	Live bacteria were transported from one infected macrophage to another. Bacteria then escape from trogocytic vesicles using their type VI secretion system (T6SS).	[20, 21]
Macrophage	Tumor cell	Reducing the dose of mAb, macrophages presented less trogocytosis and enhanced ADCC, leading to tumor cell death. Antibody engineering to increase its affinity for FcγR resulted in enhanced trogocytosis leading to tumor cell death.	[50, 53, 54]
Neutrophil	Tumor cell	ADCC of tumor cells via trogocytosis required FcγR in cooperation with the integrin CD11b/CD18 and was potentiated by blocking CD47-SIRPα interactions.	[19]
Trogocytosis is used for cell remodeling
Microglia	Neurons	Microglia control synaptic pruning during neuronal circuit formation through presynaptic trogocytosis. Microglia utilize trogocytosis for pruning retinal ganglion cell axons in the developing Xenopus laevis retinotectal circuit.	[23, 57, 59]
Astrocytes	Neurons	Astrocytes took pieces of axon projections containing mitochondria from the optic nerve neurons. Astrocytes took myelin projections at optic nerve neurons during Xenopus laevis metamorphosis.	[62, 64]
Caenorhabditis elegans endodermal cells	Primordial germ cells	Endodermal cells remove and ingest the lobes from the primordial cell body in a process named “cell cannibalism,” which resembles trogocytosis.	[11]
Xenopus laevis endodermal cells	Other endodermal cells	During metamorphosis, trailing edge retraction of migrating endodermal cells required trogocytosis by a neighboring cell.	[65]