The Lipopolysaccharide Binding Protein (LBP) is a key acute-phase protein in the body’s immune response to Gram-negative bacterial infections. This test is primarily used in the context of systemic inflammation, bacterial translocation, metabolic endotoxemia, and sepsis research. It is increasingly incorporated into diagnostic panels that assess gut barrier integrity and immune activation, making it relevant for metabolic and gastrointestinal health evaluations.
Lipopolysaccharide Binding Protein plays a pivotal role in recognizing and responding to bacterial endotoxins, specifically lipopolysaccharides (LPS) present in the outer membrane of Gram-negative bacteria. LPS enters the circulation and binds to LBP upon bacterial translocation or infection. This LBP-LPS complex then interacts with the CD14/TLR4/MD2 receptor complex on immune cells, triggering a cascade of pro-inflammatory signaling pathways. The upregulation of LBP occurs rapidly in response to microbial exposure, making its measurement a sensitive biomarker for early immune activation due to bacterial components, even in the absence of overt infection.
LBP is synthesized primarily in the liver by regulating pro-inflammatory cytokines such as interleukin-6 (IL-6). Its levels increase significantly during acute-phase responses, offering insight into the systemic burden of microbial components and the host’s immune status. Elevated LBP concentrations have been documented not only in sepsis but also in chronic low-grade inflammatory states such as obesity, type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and irritable bowel syndrome (IBS), where gut permeability is often compromised. Thus, the test is frequently used in the context of gut-liver axis research and the evaluation of intestinal dysbiosis.
Unlike direct detection of endotoxins, which is technically challenging due to their instability and low circulating concentrations, LBP provides a more stable and quantifiable proxy for LPS exposure. Furthermore, LBP is a non-invasive marker for detecting early inflammatory disturbances linked to microbial translocation in metabolic disorders with subclinical endotoxemia. Its utility expands in clinical research and diagnostics as it reflects the intersection between microbiome health, systemic inflammation, and metabolic regulation.
Quantitative analysis of LBP is performed via immunoassay, offering high sensitivity and reproducibility. The results can provide actionable insights into systemic inflammatory tone, bacterial burden, and gut barrier integrity, especially when interpreted alongside other biomarkers like CRP, IL-6, and zonulin.
See also: Lipopolysaccharide (LPS), Serum
