A Borrelia-specific monoclonal antibody binds to a flagellar epitope

In immunofluorescence assays monoclonal antibody H9724 recognized eight species of the spirochetal genus Borrelia but not representatives of the genera Treponema, Leptospira, and Spirochaeta. We examined the reactivity of H9724 against subcellular components of Borrelia hermsii, an agent of relapsing fever, and B. burgdorferi, the cause of Lyme disease. H9724 bound to isolated periplasmic flagella of the two borreliae. In Western blots the antibody reacted with the predominant protein in flagellar preparations from B. hermsii and B. burgdorferi; the apparent molecular weights of these flagellins were 39,000 and 41,000, respectively.