Fig. 2: Underlying mechanisms of trogocytosis in T cells.
From: Trogocytosis-mediated immune evasion in the tumor microenvironment
Trogocytosis is initiated by ligand‒receptor binding, which involves adhesion molecules, such as ICAM-1 and LFA-1, and other cell-specific molecules. T-cell trogocytosis occurs in a TCR affinity-dependent manner. CD28 binding to CD80/86 also triggers trogocytosis. TCR and CD28 stimulation activates the PI3K pathway, leading to cytoskeleton remodeling via actin polymerization, a key mechanism in trogocytosis. PI3K inhibitors, such as wortmannin and LY294002, reduce trogocytosis. Phosphatidylserine on activated T cells binds to Tim-3 on dendritic cells (DCs) to aid the transfer of peptide-loaded MHC molecules to T cells. Regulatory T cells capture CD80/86 on APCs through CTLA-4-mediated trogocytosis by depleting co-stimulatory molecules. CTLA-4 also removes endogenous and trogocytosed CD80/86 on T cells via cis-endocytosis.
