BDCA2 / CD303 (blood dendritic cell antigen 2)

Class

Humanized IgG1 monoclonal antibody

Pathway

Inhibits plasmacytoid dendritic cell activation and type I/III interferon production

BDCA2 (CD303) is a receptor found almost exclusively on plasmacytoid dendritic cells (pDCs), a specialized immune cell type that senses viral or self-derived nucleic acids and responds by secreting large amounts of type I and type III interferons, signaling proteins that orchestrate antiviral and inflammatory responses. In several autoimmune diseases, pDCs become chronically activated and interferon production runs persistently high, contributing to tissue inflammation and the so-called interferon signature seen in conditions such as lupus and related skin and muscle disorders. Because BDCA2 is a naturally inhibitory receptor unique to pDCs, antibodies engineered to bind and cluster it on the cell surface can dampen this interferon output selectively, without broadly suppressing other immune cell types. This selectivity is the core rationale for targeting BDCA2: rather than blocking interferon after it is released or inhibiting broad immune signaling pathways, the approach intervenes at the source cell responsible for excess production. This mechanism is relevant across autoimmune and inflammatory diseases where interferon overactivity drives pathology, including lupus erythematosus and its cutaneous and dermatomyositis-related manifestations, where reducing pDC-derived interferon is expected to translate into reduced disease activity.