BDCA2 (CLEC4C)

Class

Monoclonal antibody (humanized IgG1)

Pathway

Inhibits plasmacytoid dendritic cell activation and type I interferon production

BDCA2 (CLEC4C) is a surface receptor found almost exclusively on plasmacytoid dendritic cells (pDCs), a specialized immune cell type that senses viral and self nucleic acids and responds by producing large amounts of type I interferon, a family of signaling proteins that broadly activates immune responses. In autoimmune diseases such as lupus and related connective tissue disorders, pDCs are chronically overactivated by immune complexes containing DNA or RNA, driving a sustained interferon signature that contributes to tissue inflammation and organ damage. BDCA2 normally functions as an inhibitory receptor: when engaged, it dampens the intracellular signaling pathways that pDCs use to detect nucleic acids and manufacture interferon. A monoclonal antibody directed against BDCA2 exploits this natural brake by binding the receptor and triggering its inhibitory signaling, thereby suppressing pDC activation and reducing interferon output at the source rather than neutralizing interferon molecules or blocking their receptors downstream. This approach is being explored across autoimmune conditions where type I interferon is considered a central disease driver, including lupus, cutaneous lupus, and inflammatory myopathies. By targeting the cell type that initiates the interferon cascade, this mechanism aims to interrupt disease activity upstream of the broader inflammatory consequences that follow interferon release.