Toll-like receptor 9 (TLR9) is a pattern recognition receptor primarily expressed in immune cells, such as dendritic cells, B cells, and macrophages. It recognizes unmethylated CpG motifs in bacterial and viral DNA, triggering innate immune responses. Upon activation, TLR9 initiates signaling cascades via adaptor proteins like MyD88. leading to the production of pro-inflammatory cytokines and type I interferons. This receptor plays a critical role in host defense against pathogens but is also implicated in autoimmune diseases and chronic inflammation.
TLR9 antibodies are essential tools for studying its expression, localization, and function. They enable the detection of TLR9 in tissues or cells through techniques like Western blot, immunohistochemistry, and flow cytometry. Some antibodies block TLR9-CpG DNA interactions, aiding in mechanistic studies of immune activation or inhibition. Commercially available TLR9 antibodies vary in specificity (monoclonal vs. polyclonal) and host species origins, requiring validation for cross-reactivity in experimental models.
Research applications include exploring TLR9's role in autoimmune disorders (e.g., lupus), cancer immunotherapy (as an adjuvant), and infectious diseases. Therapeutic antibodies targeting TLR9 are under investigation to modulate aberrant immune responses. However, challenges remain in ensuring antibody specificity due to structural similarities among TLR family members. Proper controls and functional assays are critical to avoid misinterpretation in experimental outcomes.