Description: The 2D9 monoclonal antibody reacts with NOD2 protein, also known as caspase recruitment domain-containing protein 15 (CARD-15), member of a family of intracellular proteins that contain an N-terminal caspase recruitment domain (CARD), a nucleotide-binding domain (NBD), and a C-terminal regulatory domain. A NOD2 variant has been identified and termed NOD2B. RT-PCR analysis revealed expression primarily in peripheral monocytes. Expression of NOD2 or NOD2B resulted in NFKB activation, and mutants lacking the LRRs had enhanced NFKB activation. Both intact CARD domains are necessary and sufficient for IKK-gamma and RICK -dependent NFKB activation. Coimmunoprecipitation analysis showed that the CARD domain of RICK interacts with the CARD domains of NOD2. It has been proposed that NOD2 serves as an intracellular receptor for bacterial products in monocytes and transduces signals leading to NFKB activation.