Neutralization of Clostridium difficile toxin A using antibody combinations.
The pathogenicity of Clostridium difficile (C. difficile) is mediated by the release of two toxins, A and B. Both toxins contain large clusters of repeats known as cell wall binding (CWB) domains responsible for binding epithelial cell surfaces. Several murine monoclonal antibodies were generated against the CWB domain of toxin A and screened for their ability to neutralize the toxin individually and in combination. Three antibodies capable of neutralizing toxin A all recognized multiple sites on toxin A, suggesting that the extent of surface coverage may contribute to neutralization. Combination of two noncompeting antibodies, denoted 3358 and 3359, enhanced toxin A neutralization over saturating levels of single antibodies. Antibody 3358 increased the level of detectable CWB domain on the surface of cells, while 3359 inhibited CWB domain cell surface association. These results suggest that antibody combinations that cover a broader epitope space on the CWB repeat domains of toxin A (and potentially toxin B) and utilize multiple mechanisms to reduce toxin internalization may provide enhanced protection against C. difficile-associated diarrhea.
Demarest
Stephen J
SJ
Verenium Corp., San Diego, CA, USA. stephen.demarest@biogenidec.com
Hariharan
Mangala
M
Elia
Marikka
M
Salbato
Jared
J
Jin
Ping
P
Bird
Colin
C
Short
Jay M
JM
Kimmel
Bruce E
BE
Dudley
Michael
M
Woodnutt
Gary
G
Hansen
Geneviève
G
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism*; D000992:Antitoxins / Q000276:immunology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000009:adverse effects / Q000276:immunology; D001427:Bacterial Toxins / Q000009:adverse effects / Q000276:immunology; D001666:Binding Sites, Antibody / Q000276:immunology; D016466:CHO Cells; D016360:Clostridioides difficile / Q000472:pathogenicity / Q000502:physiology*; D006224:Cricetinae; D003412:Cricetulus; D003967:Diarrhea / Q000209:etiology / Q000517:prevention & control; D004338:Drug Combinations; D004761:Enterocolitis, Pseudomembranous / Q000188:drug therapy* / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology; D004768:Enterotoxins / Q000009:adverse effects / Q000276:immunology; D018604:Epitope Mapping; D006801:Humans; D051379:Mice; D011485:Protein Binding
D000911:Antibodies, Monoclonal; D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004338:Drug Combinations; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile