A three monoclonal antibody combination potently neutralizes multiple botulinum neurotoxin serotype F subtypes

作者：Fan Yongfeng; Garcia Rodriguez Consuelo; Lou Jianlong; Wen Weihua; Conrad Fraser; Zhai Wenwu; Smith Theresa J; Smith Leonard A; Marks James D^*

来源：PLos One, 2017, 12(3): e0174187.

DOI：10.1371/journal.pone.0174187

Human botulism is primarily caused by botulinum neurotoxin (BoNT) serotypes A, B and E, with around 1% caused by serotype F (BoNT/F). BoNT/F comprises at least seven different subtypes with the amino acid sequence difference between subtypes as high as 36%. The sequence differences present a significant challenge for generating monoclonal antibodies (mAbs) that can bind, detect and neutralize all BoNT/F subtypes. We used repertoire cloning of immune mouse antibody variable (V) regions and yeast display to generate a panel of 33 lead single chain Fv (scFv) mAbs that bound one or more BoNT/F subtypes with a median equilibrium dissociation constant (K-D) of 4.06 x 10(-9) M. By diversifying the V-regions of the lead mAbs and selecting for cross reactivity we generated five mAbs that bound each of the seven subtypes. Three scFv binding non-overlapping epitopes were converted to IgG that had KD for the different BoNT/F subtypes ranging from 2.2x10(-8) M to 1.47x10(-12) pM. An equimolar combination of the mAbs was able to potently neutralize BoNT/F1, F2, F4 and F7 in the mouse neutralization assay. The mAbs have potential utility as diagnostics capable of recognizing the known BoNT/F subtypes and could be developed as antitoxins to prevent and treat type F botulism.

• 出版日期2017-3-21