By: Nancy Shine, PhD, Director of R&D, List Labs

A fast, sensitive, specific and accurate detection method to determine active infection by Bacillus anthracis in plasma has been developed at List Biological Laboratories.

Bacillus anthracis is regarded as a major biological warfare threat. The inhalation form of Bacillus anthracis infection can kill quickly.  While antibiotic treatment can clear the bacterium from the host, if diagnosis is delayed, the toxin, which is rapidly produced, may already be present in lethal amounts. There is a critical need for a rapid, accurate, sensitive and simple assay to determine whether infection has occurred thereby allowing immediate treatment.

Anthrax Detection Method

Anthrax lethal factor (LF), an endopeptidase, is present in blood in the early stages of the infection.  The use of peptidic substrates in plasma is problematic due to the presence of other proteases and the likelihood of nonspecific cleavage of the substrate.  A fluorescently labeled peptide substrate, MAPKKide Plus, Prod #532, which is not cleaved by plasma proteases and thus is specific for LF has been designed. The LF is enriched by capture from plasma using an LF antibody-coated microtiter plate, and the captured LF is then exposed to the fluorescent substrate.  The amount of cleaved peptide substrate is determined by HPLC with fluorescence detection. Concentration of the LF using the antibody-coated plates allows for the detection of 5 pg LF/ml of neat plasma after 2 hours of incubation.  Alternately, the MAPKKide Plus may be added directly to diluted plasma and cleavage monitored by an increase in fluorescence as a function of time using a fluorescent microplate reader.  The limit of detection by this simpler method is 1 ng LF/ml of plasma after 5 hours of digestion.  Both methods can be confirmed by analysis of the reaction as a function of time.  These methods are described in the poster Sensitive Detection of Anthrax Lethal Factor in Plasma Using a Specific Biotinylated Fluorogenic Substrate.

What’s Next for Anthrax Detection Method

We are currently working with a biotinylated form of MAPKKide Plus to enhance the sensitivity of the simpler method using the fluorescent plate reader rather than HPLC.

You can see the poster here. To see a complete list of all of List Labs’ posters check out this blog post.

Interested in learning more about this List Labs patented peptide substrate? Contact us!

By: Rachel Berlin, Marketing Manager

List Labs is proud to be exhibiting at ASM Biothreats February 12-14th. The conference will be held in Baltimore, Maryland at the Hilton Hotel.

Thought leaders in academia, industry and government will gather to present and discuss the latest developments in the emerging field of biothreats. This year’s conference has an expanded program to include tracks on high consequence pathogen research, biological threat reduction, product development, and policy.

List Labs will be exhibiting in booth #29 and Nancy Shine will be presenting her poster on Sensitive Detection of Anthrax Lethal Factor in Plasma Using a Specific Biotinylated Fluorogenic Substrate during poster session 1 on Wednesday, February 14th from 10:30 AM- 11:30 AM in space #020. Come learn about our products that assist in the biological threat reduction such Botulinum Neurotoxins, Anthrax Lethal Factor, FRET Peptides, Shiga Toxins, Tetanus Toxins, and more! All of our research reagents are available for purchase on our website.

Visit Nancy and Karen in the List Labs booth #29, or contact us to schedule a time to meet with them at the show.  Click here for more information or to register for this conference.