Characterization of monoclonal antibodies to the plasma cell alloantigen ENPP1.

The ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) has documented roles in mineralization, nucleotide recycling, and insulin resistance. While ENPP1 was first identified as an alloantigen on mouse plasma cells (PCs), later studies revealed expression in many tissues. Previously described monoclonal antibodies against ENPP1 expressed at the cell surface recognized cells only from mice bearing the a allotype, ENPP1(a), precluding studies of mice bearing the alternative allele, ENPP1(b). Here, we characterize a novel anti-ENPP1 monoclonal antibody that recognizes both alleles and can be used for flow cytometry.