Research Article A Human/Murine Chimeric Fab Antibody Neutralizes Anthrax Lethal Toxin In Vitro

Abstract

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Human anthrax infection caused by exposure to Bacillus anthracis cannot always be treated by antibiotics. This is mostly because of the effect of the remaining anthrax toxin in the body. Lethal factor (LF) is a component of lethal toxin (LeTx), which is the major virulence of anthrax toxin. Amurine IgGmonoclonal antibody (mAb) against LF with blocking activity (coded LF8) was produced in a previous study. In this report, a human/murine chimeric Fab mAb (coded LF8-Fab) was developed from LF8 by inserting murine variable regions into human constant regions using antibody engineering to reduce the incompatibility of the murine antibody for human use.The LF8-Fab expressed in Escherichia coli could specifically identify LF with an affinity of 3.46×107 L/mol and could neutralize LeTx with an EC 50 of 8