Intercellular exchanges of membrane fragments (trogocytosis) between human muscle cells and immune cells: A potential mechanism for the modulation of muscular immune responses

Trogocytosis is a cell-contact dependent intercellular transfer of membrane fragments and associated molecules. We studied trogocytosis in the interaction of T cells with human skeletal muscle cells modeling muscle–immune cell interactions under pathophysiological conditions i.e. myositis. Human myoblasts donate membrane fragments to T cells. Acquisition of muscle-derived membrane molecules depended on T-cell activation, was independent of T-cell receptor engagement, sensitive to inhibition of actin polymerization and amplified by protein kinase C activation. Single-cell patch clamping was used to demonstrate the change in membrane capacitance upon incorporation of membrane fragments in T cells. Membrane uptake was fast and temporarily, but had clear functional consequences: T cells after intimate contact with myoblasts stimulated the proliferation of autologous T cells. Our observations raise the hypothesis that trogocytosis may modulate the outcome of T–T interactions within the micromilieu of skeletal muscle.