Summary auto-generated
This study evaluated RU 41.740, a glycoprotein immunomodulating agent derived from Klebsiella pneumoniae, using a mouse model of intra-abdominal abscess formation induced by Bacteroides fragilis, Escherichia coli, and bran. Male BALB/c mice received an abscess-inducing mixture (AIM) intraperitoneally and were treated with RU 41.740 via different routes (intraperitoneal, subcutaneous, or oral) at various timepoints. Parenteral administration of RU 41.740 before or after AIM injection significantly reduced abscess incidence and size. Oral administration proved effective only after infection, not before. Abscesses that formed in treated mice contained viable bacteria at similar concentrations to controls of equivalent size, indicating preserved host defenses. The results suggest that activation of non-specific immune defenses through RU 41.740, which enhances macrophage and neutrophil function, protects against chronic bacterial abscess development. The compound showed promise for potential clinical applications, particularly when administered orally after infection establishment.
Key findings
- Parenteral RU 41.740 significantly reduced intra-abdominal abscess incidence and size when given before or after bacterial challenge in mice
- Oral RU 41.740 (1 mg/mouse) effectively inhibited abscess development only when administered after infection (days 2, 4, 6), not before challenge
- RU 41.740-treated mice maintained normal bacterial killing capacity within abscesses compared to controls, indicating no compromise of local host defenses
- The immunomodulator activated macrophage and neutrophil functions to prevent chronic bacterial sepsis complications
- Protective effects were dose-dependent and route-dependent, with parenteral administration generally more effective than oral delivery
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Abstract
The prophylactic and therapeutic efficacies of the immunomodulating agent RU 41.740 (a glycoprotein extract from Klebsiella pneumoniae) were studied in a murine model of intra-abdominal abscess formation with Bacteroides fragilis, Escherichia coli, and bran as an abscess-potentiating agent. Parenteral injection of RU 41.740, either before or after injection of an abscess-inducing mixture (AIM), was associated with significantly diminished incidence and size of abscesses. Abscess incidence and size were significantly decreased by oral administration of RU 41.740 after, but not before, AIM injection. Abscess formation and resolution are the results of complex interactions of host defence mechanisms with bacteria and potentiating agent, and RU 41.740 has been shown previously to activate both macrophage and neutrophil function. These results indicate that activation of non-specific defences may protect against abscess development in chronic sepsis.