Consideration on difference between limulus amebocyte lysate and recombinant Factor C reagents

Abstract

 Limulus amebocyte lysate (LAL) is widely used for detection of endotoxin, one of the most potent pyrogen. Recent studies revealed the mechanism of activation of Factor C and Factor B, endotoxin binding proteins in LAL cascade. It is well known that Factor C is the first factor to bind endotoxin aggregates. The second coagulation factor, Factor B is important to achieve specificity of LAL to endotoxin because activated Factor C on endotoxin aggregates are essential for its activation. The endotoxin-specific signal is amplified after the Factor B activation in LAL. On the other hand, recombinant Factor C reagents rely on only the specificity of Factor C to endotoxin, and amplifies the trypsin-like activity of activated Factor C that may not be specific to endotoxin. This mechanism seems not to be as specific to endotoxin as LAL. More evaluation and improvement are necessary for recombinant reagents for endotoxin measurement as a safety test.