ULTRASTRUCTURE AND ANTIGENS OF THE INSERTION HOOKS OF BORRELIA-BURGDORFERI FLAGELLA

The flagella of the spirochete Borrelia burgdorferi are hollow structures ending in a funnel-shaped insertion hook that carries two aligned discs. These discs are anchored subterminally in the membrane of the cytoplasmic cylinder. The insertion hook measures about 35 nm in diameter. The monoclonal antibody LA21 reacts specifically with a 41 KD protein (flagellin) in Western blot and with recombinant flagellin in a solid phase ELISA. In immunoelectron microscopy, LA 21 binds to an antigen accessible on the outside of the insertion funnel. It can be concluded that not only flagella but also the insertion hooks consist of flagellin.