LY75

LY75 Full Name

lymphocyte antigen 75

LY75 Introduction

Lymphocyte antigen 75 (LY75), widely recognized in immunology as CD205 or DEC-205, is a large type I transmembrane glycoprotein and a prominent member of the C-type lectin receptor (CLR) family. Physiologically, LY75 is predominantly expressed on the surface of specialized antigen-presenting cells, most notably dendritic cells (DCs), as well as on thymic cortical epithelial cells. The primary biological function of LY75 is to act as a highly efficient endocytic receptor. Upon capturing extracellular glycoproteins or apoptotic cell debris, LY75 rapidly internalizes and directs these macromolecular antigens into deep, degradative late endosomal and lysosomal compartments.

Figure 1. Immune responses elicited by antigen targeting to DEC-205. (Source: Macri C, et al. 2016)

This specific intracellular routing is of paramount importance because it facilitates antigen "cross-presentation"—a critical immunological process where exogenous antigens are processed and loaded onto Major Histocompatibility Complex (MHC) class I molecules. By doing so, LY75 enables DCs to potently activate naïve CD8+ cytotoxic T lymphocytes against viral infections and tumors. Furthermore, LY75 also mediates classical MHC class II presentation to CD4+ T helper cells, thereby acting as a master molecular switch that governs the delicate balance between active cellular immunity and peripheral immune tolerance.

Because of its unique capacity to funnel antigens directly into the immune system's cross-presentation machinery, LY75 has become a highly attractive target in clinical oncology and vaccine development. In cancer immunotherapy, researchers engineer chimeric vaccines by fusing tumor-specific antigens to anti-LY75 antibodies, successfully steering these antigens directly to DCs to elicit a robust, systemic anti-tumor T-cell response. Beyond its role in DC targeting, aberrant overexpression of LY75 has been documented in various hematological malignancies, such as diffuse large B-cell lymphomas, as well as in multiple solid tumors, including ovarian, bladder, and gastric carcinomas. Because the receptor naturally internalizes its bound cargo so rapidly, tumor-associated LY75 serves as an ideal molecular conduit for targeted therapeutics. Consequently, LY75 is currently being rigorously investigated in clinical trials as a target for novel antibody-drug conjugates (ADCs). These ADCs exploit the LY75 receptor to specifically deliver highly potent cytotoxic payloads directly into the cytoplasm of malignant cells, sparing healthy tissues and opening a promising new frontier in precision oncology.

Alternate Names for LY75

LY75; lymphocyte antigen 75; CD205; DEC205; DEC-205; ly-75;

• 1. Macri C, et al. Targeting dendritic cells: a promising strategy to improve vaccine effectiveness. Clin Transl Immunology. 2016 Mar 18;5(3):e66.
  2. Bonifaz LC, et al. In vivo targeting of antigens to maturing dendritic cells via the DEC-205 receptor improves T cell vaccination. J Exp Med. 2004 Mar 15;199(6):815-24.