Targeting mucosal dendritic cells with microbial antigens from probiotic lactic acid bacteria

Abstract

The use of vaccines against infectious microbes has been critical to the advancement of medicine. Vaccine strategies combined with, or without, adjuvants have been established to eradicate various bacterial and viral pathogens. A new generation of vaccines is being developed using specific strains of Gram-positive, lactic acid bacteria and, notably, some probiotic lactobacilli. These bacteria have been safely consumed by humans for centuries in fermented foods. Thus, they can be orally administered, are well tolerated by recipients and could be easily and economically provided to large populations. In this overview, we focus on mucosal immunity and how its cellular component(s), particularly dendritic cells, can be specifically targeted to deliver immunogenic subunits, such as the protective antigen from Bacillus anthracis (the causative agent of anthrax). An antigen-specific immune response can be elicited using specific strains of Lactobacillus acidophilus expressing the protective antigen. A mucosal, dendritic cell-targeted approach increases the bioavailability of an immunogen of interest when delivered orally by L. acidophilus. This provides an efficiently elegant natural strategy and serves a dual function as an immune-stimulating adjuvant in vivo.

Keywords::

• adjuvant
• dendritic cell
• M cell
• macrophage
• mucosal immunity
• probiotic bacteria
• T regulatory cell
• targeting antigen by specific dendritic cell-binding peptides
• Th17 cell
• vaccine delivery

Financial & competing interests disclosure

The views, opinions and/or findings contained in this report are those of the authors and should not be construed as an official Department of the Army, Johns Hopkins, or North Carolina State University position, policy, or decision unless designated by other documentation. We thank Dr. Bradley Stiles for fruitful discussion. T Duong was supported by an NSF Fellowship in Functional Genomics at North Carolina State University, and research support from the NC Dairy Foundation and the National Institutes of Health, project # AI059590. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.