Next Article in Journal
Glucose-6-Phosphate Dehydrogenase Enhances Antiviral Response through Downregulation of NADPH Sensor HSCARG and Upregulation of NF-κB Signaling
Next Article in Special Issue
Development of an Assay for the Identification of Receptor Binding Proteins from Bacteriophages
Previous Article in Journal / Special Issue
A Flagellar Glycan-Specific Protein Encoded by Campylobacter Phages Inhibits Host Cell Growth
Article Menu

Export Article

Open AccessCommunication
Viruses 2015, 7(12), 6675-6688;

Development of Phage Lysin LysA2 for Use in Improved Purity Assays for Live Biotherapeutic Products

Office of Vaccines Research and Review, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
Author to whom correspondence should be addressed.
Academic Editors: Abram Aertsen and Rob Lavigne
Received: 29 September 2015 / Revised: 30 November 2015 / Accepted: 10 December 2015 / Published: 16 December 2015
Full-Text   |   PDF [9041 KB, uploaded 16 December 2015]   |  


Live biotherapeutic products (LBPs), commonly referred to as probiotics, are typically preparations of live bacteria, such as Lactobacillus and Bifidobacterium species that are considered normal human commensals. Popular interest in probiotics has been increasing with general health benefits being attributed to their consumption, but there is also growing interest in evaluating such products for treatment of specific diseases. While over-the-counter probiotics are generally viewed as very safe, at least in healthy individuals, it must be remembered that clinical studies to assess these products may be done in individuals whose defenses are compromised, such as through a disease process, immunosuppressive clinical treatment, or an immature or aging immune system. One of the major safety criteria for LBPs used in clinical studies is microbial purity, i.e., the absence of extraneous, undesirable microorganisms. The main goal of this project is to develop recombinant phage lysins as reagents for improved purity assays for LBPs. Phage lysins are hydrolytic enzymes containing a cell binding domain that provides specificity and a catalytic domain responsible for lysis and killing. Our approach is to use recombinant phage lysins to selectively kill target product bacteria, which when used for purity assays will allow for outgrowth of potential contaminants under non-selective conditions, thus allowing an unbiased assessment of the presence of contaminants. To develop our approach, we used LysA2, a phage lysin with reported activity against a broad range of Lactobacillus species. We report the lytic profile of a non-tagged recombinant LysA2 against Lactobacillus strains in our collection. We also present a proof-of-concept experiment, showing that addition of partially purified LysA2 to a culture of Lactobacillus jensenii (L. jensenii) spiked with low numbers of Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus ) effectively eliminates or knocks down L. jensenii, allowing for clear detection of the contaminating strains. With continued identification and characterization of phage lysins, we hope that the use of recombinant phage lysins in purity assays for products containing live microbials may offer additional tools to help advance product development of LBPs. View Full-Text
Keywords: endolysin; live biotherapeutic product; probiotics; purity assay; phage lysins; LysA2; Lactobacillus endolysin; live biotherapeutic product; probiotics; purity assay; phage lysins; LysA2; Lactobacillus

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Dreher-Lesnick, S.M.; Schreier, J.E.; Stibitz, S. Development of Phage Lysin LysA2 for Use in Improved Purity Assays for Live Biotherapeutic Products. Viruses 2015, 7, 6675-6688.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Viruses EISSN 1999-4915 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top