Diversity in lipid A binding ligands: comparison of lipid A monoclonal antibodies with rBPI23.

1. Mabs with a high affinity for free lipid A do not bind when it is covalently linked, i.e. in the form of LPS. 2. Lipid A-binding Mabs may be divided into three categories: I. Monoreactive Mabs that bind to the hydrophillic backbone of lipid A II. Polyreactive Kdo Mabs III. Polyreactive Mabs that bind by hydrophobic interactions 3. rBPI23 binds either free or covalently linked lipid A.