CD335, also known as NKp46 or Natural Cytotoxicity Triggering Receptor 1 （NCR1）, is a 46 kDa type I transmembrane glycoprotein that belongs to the natural cytotoxicity receptor family. It is primarily expressed on natural killer （NK） cells and plays a crucial role in their activation and cytotoxicity. CD335 can recognize and bind to viral hemagglutinins and heparan sulfate proteoglycans on target cells, triggering NK cell-mediated cytotoxic responses. This receptor is involved in non-MHC-restricted natural cytotoxicity and is essential for the immune system's ability to detect and eliminate infected or transformed cells.