Host: Goat Polyclonal
Lipid A is a lipid component of an endotoxin held responsible for toxicity of Gram-negative bacteria. Sensing of lipid A by the human immune system may also be critical for the onset of immune responses to Gram-negative infection, and for the subsequent successful fight against the infection. Lipid A is located at one end of the lipopolysaccharide (LPS, also called endotoxin) molecule, and anchors the LPS to the outer membrane of a Gram-negative bacteria. Many of the immune activating abilities of LPS can be contributed to the lipid A unit. It is a very potent stimulant of the immune system, activating cells (for example, monocytes or macrophages) at picogram per milliliter quantities. When present in the body at high concentrations during a Gram-negative bacterial infection, it may cause shock and death by an "out of control" excessive immune reaction.