NOD3 is a member of the NOD (nucleotide-binding oligomerization domain) family, a group of proteins that are involved in innate immune defense. NOD3 also known as NLR family CARD containing 3 (NLRC3), is predominantly expressed in the immune system, particularly in T lymphocytes, and its expression is strongly down-regulated following stimulation of the T-cell receptor complex and CD28, suggesting that NOD3 plays a role in attenuating the activation of T cells. NOD3 inhibits NF-κB, AP-1 and NFAT transcriptional activation in Jurkat T cells downstream of CD3/CD28 stimulation or treatment with PMA/ionomycin and decreases IL-2 and CD25 mRNA induction in activated cells.