Exchanges of membrane patches (trogocytosis) split theoretical and actual functions of immune cells.

Exchanges of antigens between immune cells have long been evidenced in the murine system and more recently in humans, but the mechanisms by which these transfers occur, and even more so their functional and physiologic significance remain unclear. Yet, intercellular antigen exchanges, and particularly intercellular exchanges of intact membrane patches, also called trogocytosis, have recently been the subject of renewed interest. Indeed, trogocytosis has been thoroughly investigated in terms of phenomenology, mechanisms and parameters, and function. For lack of a dramatic function for trogocytosis, the possible significance of membrane patch transfers has been discussed. Here, we will briefly outline the key findings concerning trogocytosis, highlight their significance, and discuss how they have an impact on commonly accepted immune mechanisms.