Used in immunological research to study Toll-like receptor 4 (TLR4) signaling pathways involved in innate immunity. Enables investigation of host responses to bacterial lipopolysaccharides (LPS) and inflammatory mechanisms. The His tag facilitates easy purification and detection in protein expression systems. Commonly applied in ELISA, Western blotting, and protein-protein interaction studies. Supports development of vaccines and immunotherapies by serving as a target antigen or stimulant in cell-based assays.