The bactericidal/permeability-increasing protein (BPI) in antibacterial host defense

Area of Science:

• Biochemistry
• Immunology
• Microbiology

Background:

• Bactericidal/permeability-increasing protein (BPI) is a cationic protein found in polymorphonuclear leukocytes.
• BPI exhibits potent, specific cytotoxicity against Gram-negative bacteria (GNB) by binding to lipopolysaccharides (LPS).
• BPI neutralizes LPS-induced host inflammatory responses.

Purpose of the Study:

• To evaluate the therapeutic potential of BPI and its recombinant amino-terminal fragments.
• To assess the safety and efficacy of BPI in preclinical and clinical settings.

Main Methods:

• Studies involved complex formation of BPI with LPS, bacterial growth arrest assays, and inner membrane damage assessment.
• Preclinical animal studies tested protection against LPS and GNB.
• Clinical trials (Phase I, II, and III) were conducted in healthy volunteers and patients with severe infections.

Main Results:

• BPI binding to LPS causes immediate bacterial growth arrest and subsequent inner membrane damage.
• The amino-terminal half of BPI retains both antibacterial and anti-endotoxin activities.
• Animal studies demonstrated protection against lethal LPS and GNB challenges.
• Clinical trials involving over 900 individuals showed no safety or immunogenicity issues, with preliminary evidence of overall patient benefit.

Conclusions:

• Recombinant BPI fragments are potent antibacterial and anti-endotoxin agents.
• BPI demonstrates a favorable safety profile and therapeutic potential.
• BPI may be a valuable treatment for life-threatening infections and conditions involving bacteremia and endotoxemia.