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Engineering Microbes for Therapy

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Front. Microbiol. | doi: 10.3389/fmicb.2018.02264

Engineering components of the Lactobacillus S-layer for biotherapeutic applications

  • 1Genomic Sciences Graduate Program, North Carolina State University, United States
  • 2Department of Food, Bioprocessing & Nutrition Sciences, North Carolina State University, United States

Lactic acid bacteria (LAB) are frequently harnessed for the delivery of biomolecules to mucosal tissues. Several species of Lactobacillus are commonly employed for this task, of which a subset are known to possess surface-layers (S-layers). The S-layer is a two-dimensional crystalline array of repeating proteinaceous subunits that forms the outermost coating of many prokaryotic cell envelopes. Its periodicity and abundance have made it a target for numerous biotechnological applications, including delivery of therapeutic proteins and vaccine antigens. In the following review, we examine the multi-faceted S-layer protein (Slp), and its use in both heterologous protein expression and mucosal vaccine delivery, through its diverse genetic components: the strong native promoter, capable of synthesizing as many as 500 Slp subunits per second; the signal peptide that stimulates robust secretion of target proteins; and the structural domains, which can be harnessed for both cell surface display of a foreign peptide or adhesion enhancement of a host bacterium. Although numerous studies have established vaccine platforms based on one or more components of the Lactobacillus S-layer, this area of research remains largely in its infancy, thus this review not only highlights past works, but also advocates for the future use of Slps in mucosal vaccine research.

Keywords: Lactobacillus, probiotic, S-layer, Biotherapeutic, Mucosal vaccine, CRISPR

Received: 05 Jun 2018; Accepted: 05 Sep 2018.

Edited by:

Aleš Berlec, Jožef Stefan Institute (IJS), Slovenia

Reviewed by:

Akinobu Kajikawa, Tokyo University of Agriculture, Japan
Olivia Cano Garrido, Centre for Research in Agricultural Genomics (CRAG), Spain  

Copyright: © 2018 Klotz and Barrangou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Rodolphe Barrangou, North Carolina State University, Genomic Sciences Graduate Program, Raleigh, United States,