Lipopolysaccharide (LPS)

Definition

Lipopolysaccharide (LPS) is a large molecule found in the outer membrane of Gram-negative bacteria. It plays a crucial role in bacterial pathogenicity and triggers strong immune responses in hosts.

5 Must Know Facts For Your Next Test

1. LPS is composed of lipid A, core polysaccharide, and O antigen.
2. Lipid A is responsible for the toxic effects of LPS and can cause septic shock.
3. LPS acts as an endotoxin that can trigger inflammation and fever in the host.
4. It is recognized by toll-like receptor 4 (TLR4) on immune cells, initiating an innate immune response.
5. LPS contributes to the structural integrity of the bacterial cell wall, protecting against certain chemical attacks.

Review Questions

• What are the three main components of LPS?
• How does LPS contribute to septic shock?
• Which receptor on immune cells recognizes lipopolysaccharides?

Related terms

Gram-negative bacteria: Bacteria characterized by a thin peptidoglycan layer and an outer membrane containing LPS.

Endotoxin: A toxin that is part of the outer membrane of Gram-negative bacteria, often synonymous with LPS.

Toll-like receptor 4 (TLR4): A protein on immune cells that recognizes LPS and initiates an innate immune response.