Neutrophil recruitment in Clostridium difficile toxin A enteritis in the rabbit.
Neutrophil infiltration is a prominent feature of Clostridium difficile-associated enteritis and colitis. The aim of this study was to examine the importance of neutrophil recruitment and neutrophil-mediated tissue damage in C. difficile toxin A-induced enteritis. Competitive binding experiments using purified 3H-toxin A demonstrated the presence of a single class of medium affinity receptors on rabbit neutrophils (Kd 7 x 10(-8) M). Pertussis toxin and the nonhydrolyzable GTP analog GTPgamma S both inhibited 3H-toxin A binding (by 56 and 65%, respectively), indicating that the rabbit neutrophil toxin A receptor is G protein linked. Toxin A elicited a dose-dependent (25-200 micrograms/ml) stimulation of neutrophil migration in vitro, and this functional effect was also pertussis toxin sensitive (69% inhibition). Treatment of neutrophils with R15.7, a blocking monoclonal antibody to the leuocyte adhesion molecule CD18, inhibited toxin A-stimulated neutrophil migration by 85% in vitro. Pretreatment of rabbits with R15.7 also prevented neutrophil infiltration of toxin A-exposed ileal loops in vivo as determined by histologic examination and by ileal tissue myeloperoxidase levels. Furthermore, R15.7 effected a substantial inhibition of fluid secretion (by 65%), mannitol permeability (by 66%), and histologic damage in toxin A-exposed ileal loops. Anti-CD18 (R15.7) had no inhibitory effect on cholera toxin enterotoxicity. These data demonstrate that C. difficile toxin A is a proinflammatory toxin whose enterotoxic effects are substantially dependent upon neutrophil recruitment.
Kelly
C P
CP
Section of Gastroenterology, Boston University School of Medicine, Massachusetts 02118.
Becker
S
S
Linevsky
J K
JK
Joshi
M A
MA
O'Keane
J C
JC
Dickey
B F
BF
LaMont
J T
JT
Pothoulakis
C
C
D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D001427:Bacterial Toxins / Q000633:toxicity*; D018821:CD18 Antigens; D016360:Clostridioides difficile / Q000472:pathogenicity*; D004751:Enteritis / Q000097:blood / Q000209:etiology*; D004768:Enterotoxins / Q000378:metabolism / Q000633:toxicity*; D019204:GTP-Binding Proteins / Q000502:physiology; D008297:Male; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D011817:Rabbits
D015703:Antigens, CD; D001427:Bacterial Toxins; D018821:CD18 Antigens; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; D019204:GTP-Binding Proteins