Bacterial fragments

Bacterial fragments is a broad, non-specific term referring to various structural components of bacteria, such as lipopolysaccharides (LPS), peptidoglycans, flagellin, and bacterial DNA (CpG motifs). These components are recognized by the host immune system as Pathogen-Associated Molecular Patterns (PAMPs) through specialized Pattern Recognition Receptors (PRRs) like Toll-like receptors (TLRs). While they are not therapeutic targets in the traditional sense of a specific human protein, they are often used as active ingredients in bacterial lysates or vaccines to modulate immune responses. In clinical pathology, the presence of these fragments in the bloodstream is a primary driver of sepsis and systemic inflammation. Because the term encompasses a wide variety of chemically distinct molecules rather than a single molecular entity, it is generally considered too vague for precise pharmacological targeting.

Other names

Bacterial lysatesPathogen-associated molecular patternsPAMPsBacterial componentsBacterial antigens

Bacterial fragments typically act as ligands for Pattern Recognition Receptors (PRRs) such as Toll-like receptors (TLRs) and NOD-like receptors (NLRs) to stimulate the innate immune system.