IDENTIFICATION AND CHARACTERIZATION OF A NEUTRALIZING MONOCLONAL-ANTIBODY AGAINST BOTULINUM NEUROTOXIN, SEROTYPE-F, FOLLOWING VACCINATION WITH ACTIVE TOXIN

Clostridium botulinum may produce any of seven known serotypes of neur otoxin (BoNT/A-/G), which are the most toxic bacterial proteins known, Efforts to develop a second-generation vaccine to these toxins would benefit from the isolation of hybridomas producing neutralizing monocl onal antibodies (MAbs), We hypothesized that previous efforts to isola te neutralizing MAbs against various BoNTs failed due to use of toxoid ed, chemically altered antigens, We employed a novel vaccination regim en employing native, active, single-chain BoNT/E (scBoNT/E), A number of the BoNT/E immunized mice were further vaccinated Kith lethal doses of fully active BoNT/F. MAb 7F8 consistently neutralized BoNT/F in th ree different assays: in vivo neutralization, passive neutralization, and neutralization of regional paralysis, There was no detectable reco gnition and essentially no neutralization of scBoNT/E. The epitope rec ognized by this MAb was denatured when treated with formalin, urea, gu anidine chloride, or sodium dodecyl sulfate, Preliminary epitope mappi ng studies indicate that the MAb bound to a conformational epitope.