Trogocytosis: Emerging insights into cellular communication, immunity, and pathogenesis.

Trogocytosis is a unique intercellular process that can occur when two cells become in contact to each other and one cell "nibbles" portions of another cell's membrane and surface molecules. This phenomenon is widely observed among immune cells such as B cells, T cells, NK cells, and antigen-presenting cells (APCs). Through trogocytosis, molecules including major histocompatibility complexes (MHC), costimulatory receptors, and antigens are transferred, influencing cellular communication and immune regulation. While trogocytosis supports processes like antigen presentation, immune activation, and neural remodeling, it also contributes to pathological conditions, including tumor immune evasion, therapeutic resistance, and pathogen dissemination. This duality raises critical questions about its overall impact: is trogocytosis a friend or foe to the immune system? By comparing trogocytosis to phagocytosis, exploring molecular mechanisms, and examining its roles in health and disease, this review synthesizes current findings and highlights areas for future investigation. Understanding the precise mechanisms governing trogocytosis could pave the way for innovative therapies targeting infections, cancers, and autoimmune disorders.