title: Catalytically inactive anthrax toxin(s) are potential prophylactic agents.
abstract: The anthrax exotoxin, which is a key mediator of anthrax related pathogenesis, is composed of two separate toxins formed by pairwise combinations of three proteins that are encoded on the pXO1 plasmid of Bacillus anthracis. Lethal toxin is composed of protective antigen (PA) combined with lethal factor (LF) while edema toxin is composed of PA and edema factor (EF). The present study found that the catalytic mutants of LF (LFE687A) and EF (EFH351A) competitively inhibited lethal toxin and edema toxin-mediated activity in vitro and lethality in vivo and were non-toxic to sensitive cell lines when combined with PA. While PA combined with EFH351A was non-lethal in mice, PA combined with LFE687A was of reduced virulence. Full protection of mice against a lethal toxin challenge required injection of mice with PA combined with both LFE687A and EFH351A. The potential use of these full-length, biologically inactive mutant proteins combined with PA as prophylactics or therapeutics is discussed.
authors.affiliation: School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India.
authors.forename: Megha
authors.initials: M
authors.lastname: Gupta
authors.forename: Sheeba
authors.initials: S
authors.lastname: Alam
authors.forename: Rakesh
authors.initials: R
authors.lastname: Bhatnagar
mesh_terms: D000818:Animals; D000881:Anthrax / Q000276:immunology / Q000517:prevention & control*; D022122:Anthrax Vaccines / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D001408:Bacillus anthracis / Q000235:genetics* / Q000276:immunology* / Q000472:pathogenicity*; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D016466:CHO Cells; D002384:Catalysis; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D008264:Macrophages; D051379:Mice; D009154:Mutation
chemical_list: D022122:Anthrax Vaccines; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; C030325:anthrax toxin