Monoclonal antibody (mAb) 927 recognizes CD317 (BST2; PDCA-1)1. CD317 is a specific marker of IFN-producing cells (IPCs aka plasmacytoid dendritic cells, DC) under naïve conditions. IPCs are early responders to viral infection and direct both the innate and adaptive immune response2,3. CD317 also promotes secretion in IPCs, presumably by sorting proteins between the Golgi apparatus and plasma membrane1. CD317 is located on the cell surface as well as intracellularly in the Golgi apparatus and is associated with lipid rafts.
CD317 is primarily present on the cell surfaces of murine IPCs in naïve mice, where its expression on resting and activated IPCs is independent of IFNs1. However, when stimulated with type I IFNs and IFN-gamma, cell surface expression of CD317 is induced on most cell types. When administered in vivo, treatment with mAb 927 abrogates IFN-α secretion by IPCs in response to CpG as well as depletes IPCs ~ 95%, significantly reducing plasma cells.
The 927 clone was generated to overcome barriers to the identification and study of IPCs caused by their scarcity in blood and tissues as well as their complex surface phenotype1. mAb 927 was generated by immunizing Wistar/CRL rats with bone marrow-derived IPCs with either CpG oligodeoxynucleotide 1826 or heat-killed Mycobacteria tuberculosis as adjuvant. Hybridoma lines were created by fusing popliteal lymph nodes with SP2/0 myeloma cells. Supernatants were screened for lines that recognize CD11c+B220+Ly-6c+CD11b-splenocytes. mAb 927 is rat IgG2b isotype.
