CARD9 (Caspase recruitment domain-containing protein 9) is a pivotal adaptor protein in innate immunity, primarily involved in antifungal defense and inflammatory signaling. Structurally, it contains an N-terminal CARD domain and a coiled-coil domain, enabling interactions with other signaling molecules like BCL10 and MALT1 to form the CARD9-BCL10-MALT1 (CBM) complex. This complex activates downstream pathways, including NF-κB and MAPK, triggering cytokine production and immune cell activation. CARD9 is predominantly expressed in myeloid cells (e.g., dendritic cells, macrophages), linking pathogen recognition by receptors (e.g., Dectin-1) to adaptive immune responses.
Research highlights CARD9's critical role in fungal immunity, as mutations in CARD9 are linked to susceptibility to invasive fungal infections (e.g., candidiasis, aspergillosis). Dysregulated CARD9 signaling is also implicated in autoimmune and inflammatory disorders, such as inflammatory bowel disease (IBD) and rheumatoid arthritis. Anti-CARD9 antibodies are essential tools for studying these mechanisms, enabling detection of protein expression, localization, and interactions via techniques like Western blot, immunohistochemistry, and co-immunoprecipitation. Commercial antibodies are typically validated for specificity across human, mouse, and rat models, aiding both basic research and clinical investigations into immune dysregulation. Understanding CARD9 pathways offers potential therapeutic targets for modulating immune responses in infection and chronic inflammation.