Lipopolysaccharides, fromProteus mirabilis, are endotoxins derived from the bacterium Proteus mirabilis, functioning as TLR-4 activators and featuring an S-type LPS structure. They play a role in activating pathogen-associated molecular patterns (PAMP) and inducing cell-extracellular vesicle release. These lipopolysaccharides have a classic tripartite structure: O antigen, core oligosaccharide, and lipid A. Proteus mirabilis is a primary pathogen responsible for urinary tract infections and has potential links to rheumatoid arthritis. Additionally, Lipopolysaccharides, fromProteus mirabilis, exhibit promising antitumor effects, showing in vivo inhibitory activity against solid tumors such as meningeal sarcoma and Walker carcinoma.