Bacterial/Permeability-Increasing Protein

Athens Research

Bacterial/Permeability-Increasing Protein

9

Antimicrobial, Inflammation, In Vitro Diagnostic, Cell based assays, ANCA related vasculitis

Research Use Only

≥95% by SDS-PAGE

Bactericidal permeability-increasing protein

Bactericidal/Permeability-Increasing Protein (BPI) is a cationic glycoprotein stored in azurophilic granules of polymorphonuclear leukocytes (PMNs). Its boomerang-shaped structure features two functional domains: an N-terminal region (residues 1–199) responsible for antimicrobial and endotoxin-neutralizing activities, and a C-terminal domain facilitating opsonization and immune cell interactions. BPI selectively targets Gram-negative bacteria via high-affinity binding (Kd ~2–5 nM) to lipopolysaccharides (LPS), disrupting outer membrane integrity through hydrophobic pocket interactions with lipid A, leading to bacterial permeabilization and death. Additionally, BPI inhibits LPS-induced immune activation by blocking interactions with LPS-binding protein (LBP) and CD14, thereby attenuating cytokine storms. Clinically, BPI serves as a major autoantigen for anti-neutrophil cytoplasmic antibodies (ANCA) in systemic vasculitis, particularly in patients with chronic Gram-negative infections like cystic fibrosis or inflammatory bowel disease. BPI-ANCA immune complexes induce neutrophil extracellular trap (NET) formation via TNFalfa-primed neutrophils, exacerbating vascular inflammation and contributing to pauci-immune glomerulonephritis and cutaneous vasculitis. Elevated BPI levels (more then45 ng/mL) also correlate with sepsis severity and mortality, serving as a prognostic biomarker. Therapeutically, recombinant N-terminal fragments (e.g., rBPI21) demonstrate efficacy in neutralizing endotoxin and improving survival in meningococcal sepsis models. Clinical trials highlight its potential in hemorrhagic trauma and peritoneal infections, while synthetic BPI mimetics and monoclonal antibodies targeting BPI-ANCA pathways are under investigation for vasculitis. These applications underscore BPI’s dual role as a sentinel of innate immunity and a bridge to autoimmune pathology.

more then 1 year

Neutrophils shown to be non reactive for HBsAg, anti-HCV, anti-HBc, and negative for anti-HIV 1 & 2 by FDA approved tests.

≤ -80° C

41116100