Juntendo Medical Journal
Online ISSN : 2188-2126
Print ISSN : 2187-9737
ISSN-L : 2187-9737
Current Topics: Current Status and Future Perspective on the Application of Host Defense Peptides to Medicine
Bacterial Endotoxin Assays Relevant to Host Defense Peptides
Author information

2016 Volume 62 Issue 2 Pages 132-140


The Limulus amoebocyte lysate (LAL) test is the most sensitive and reliable assay for the detection of trace amounts of bacterial endotoxins (lipopolysaccharides, or LPS), and is an accepted in vitro alternative to the rabbit pyrogen test for evaluations of parenteral drugs, biological products, and medical devices. There are three principal LAL tests, which can be categorized as both semi-quantitative and quantitative methods, including gel-clot, turbidimetric, and chromogenic assays. Since the 1970s, these tests have been successfully formulated and commercialized by US and Japanese manufacturers. More recently, in addition to the recombinant factor C-based assay, a novel product containing all of the recombinant coagulation factors from horseshoe crab has been developed, which may lead to the creation of a next generation LAL alternative. Furthermore, there are antimicrobial peptides called “host defense peptides (HDPs)” that play a key role in innate immune responses. The LAL test for HDP-related studies is challenging, because the active site of endotoxin could be masked by the binding with HDPs. Thus, it is very important to properly evaluate the actions of HDPs (human defensins and cathelicidin peptide LL-37) such as the neutralization of LPS, immunostimulatory functions, and anti-endotoxin activity. Moreover, sensitive detection of LPS in cell culture media should be conducted to address the problem of endotoxin contamination in the media. Here, we discuss the progress of LAL-based endotoxin assay technologies, as well as their applications and limitations, with a focus on innovative functional studies of HDPs.

Information related to the author
© 2016 The Juntendo Medical Society. This is an open access article distributed under the terms of Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original source is properly credited.
Previous article Next article