Structure-function analysis of Bacillus anthracis edema factor by using monoclonal antibodies.
Edema toxin of Bacillus anthracis is composed of protective antigen (PA) and edema factor (EF), a calcium- and calmodulin-dependent adenylate cyclase. At least five different antigenic regions of EF were identified using a competitive-binding, enzyme-linked immunosorbent assay of paired monoclonal antibodies (mAbs). Two mAbs, 9F5 and 7G10, inhibited the binding of 125I-EF to cell-bound PA. However, only 9F5 inhibited the elongation response of Chinese hamster ovary cells in the presence of edema toxin. Cleavage of EF at the two aspartic acid-proline residues by acid hydrolysis resulted in three fragments: a C-terminal 17 kDa fragment, a central 53 kDa fragment, and an N-terminal 18 kDa fragment. Immunoblots of EF cleaved by formic acid mapped mAbs 9F5 and 7G10 to the N-terminal 18 kDa fragment, mAb 1E6 to the C-terminal 17 kDa fragment, and the remaining 7 mAbs to the central 53 kDa fragment. mAbs 7G10 and 9F5 defined an antigenic region within amino acids 1-156 of EF which is involved in interaction with PA in forming edema toxin.
Little
S F
SF
U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702.
Leppla
S H
SH
Burnett
J W
JW
Friedlander
A M
AM
D000067956:Adenylyl Cyclase Inhibitors; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000942:Antigens, Bacterial; D001408:Bacillus anthracis; D001427:Bacterial Toxins / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology*; D001710:Biotin; D016466:CHO Cells; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015151:Immunoblotting; D007074:Immunoglobulin G; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology
D000067956:Adenylyl Cyclase Inhibitors; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D007074:Immunoglobulin G; D010446:Peptide Fragments; C030325:anthrax toxin; D001710:Biotin