Polysaccharide-mediated protection against abscess formation in experimental intra-abdominal sepsis.
Abscess formation is a major complication of intra-abdominal sepsis that causes significant morbidity and mortality. In such cases, Bacteroides fragilis is the predominant anaerobic isolate. In a rat model of intra-abdominal sepsis, the capsular polysaccharide complex (CPC) from B. fragilis promotes abscess formation and when administered sub-cutaneously, protects against this host response by a T cell-dependent immune mechanism. In the present study, the polysaccharide A (PS A) component of CPC protected animals against challenge with live heterologous bacterial species (mixtures of anaerobes and facultative organisms) that are most commonly isolated from intra-abdominal abscesses in humans. Protection against heterologous bacterial challenge was transferred by T cells. Administration of PS A shortly before or even after challenge with B. fragilis protected against this host response. In experiments designed to simulate fecal contamination of the human peritoneal cavity, PS A protected animals against abscess formation induced by a rat cecal contents inoculum. The surprisingly broad protective activity of PS A indicates that this molecule is likely suppressing a nonspecific host tissue reaction that forms in response to a variety of abscess-inducing organisms and that it might be useful in preventing abscess formation associated with intra-abdominal sepsis in the clinical setting.
Tzianabos
A O
AO
Channing Laboratory, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Kasper
D L
DL
Cisneros
R L
RL
Smith
R S
RS
Onderdonk
A B
AB
D018784:Abdominal Abscess / Q000276:immunology / Q000517:prevention & control*; D000818:Animals; D016470:Bacteremia / Q000276:immunology / Q000517:prevention & control*; D001442:Bacteroides Infections / Q000276:immunology / Q000517:prevention & control*; D001441:Bacteroides fragilis / Q000276:immunology; D003429:Cross Reactions; D004195:Disease Models, Animal; D004754:Enterobacter / Q000276:immunology; D005243:Feces / Q000382:microbiology; D006801:Humans; D007114:Immunization; D008297:Male; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013601:T-Lymphocytes / Q000276:immunology
D011135:Polysaccharides, Bacterial