CD303, also known as BDCA-2 or CLEC4C, is a 38 kD type II transmembrane glycoprotein and a member of the C-type lectin superfamily. It is specifically expressed on plasmacytoid dendritic cells (pDCs) and plays a crucial role in antigen capture and processing, as well as in cell adhesion and signaling. CD303 is involved in the presentation of antigens to T cells and can mediate the inhibition of IFN-伪/尾 expression in pDCs when cross-linked. This molecule is also a potential therapeutic target in diseases such as systemic lupus erythematosus due to its role in immune regulation.