Recombinant Invasive Lactococcus lactis Carrying a DNA Vaccine Coding the Ag85A Antigen Increases INF-γ, IL-6, and TNF-α Cytokines after Intranasal Immunization

Abstract

Tuberculosis (TB) remains a major threat throughout the world and in 2015 it caused the death of 1.4 million people. The Bacillus Calmette-Guérin is the only existing vaccine against this ancient disease; however, it does not provide complete protection in adults. New vaccines against TB are eminently a global priority. The use of bacteria as vehicles for delivery of vaccine plasmids is a promising vaccination strategy. In this study, we evaluated the use of, an engineered invasive Lactococcus lactis (expressing Fibronectin-Binding Protein A from Staphylococcus aureus) for the delivery of DNA plasmid to host cells, especially to the mucosal site as a new DNA vaccine against tuberculosis. One of the major antigens documented that offers protective responses against Mycobacterium tuberculosis is the Ag85A. L. lactis FnBPA+ (pValac:Ag85A) which was obtained and used for intranasal immunization of C57BL/6 mice and the immune response profile was evaluated. In this study we observed that this strain was able to produce significant increases in the amount of pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-6) in the stimulated spleen cell supernatants, showing a systemic T helper 1 (Th1) cell response. Antibody production (IgG and sIgA anti-Ag85A) was also significantly increased in bronchoalveolar lavage, as well as in the serum of mice. In summary, these findings open new perspectives in the area of mucosal DNA vaccine, against specific pathogens using a Lactic Acid Bacteria such as L. lactis.

Adjuvant Strategies for Lactic Acid Bacterial Mucosal Vaccines

“…The surface display of enterocyte-targeting bacterial proteins by L. lactis resulted in delivery of DNA plasmids to enterocytes and protein secretion into the intestinal lumen. This is a potential alternative strategy of protein antigen delivery and could also be utilized to deliver DNA to promote secretion of anti-viral or bacterial peptides [98][99][100][101]. Another reported benefit of these bacterial vectors is the ability to outcompete pathogens at mucosal surfaces.…”

“…Targeting LAB though surface expression of enterocyte binding proteins has been explored with the non-invasive LAB, L. lactis, through the use of Listeria monocytogenes internalin A (InIA) and/or Staphylococcus aureus fibronectin binding protein A (FnBPA) [97][98][99][100][101]. InlA is a cell wall protein that allows L. monocytogenes to bind and be internalized by epithelial cells [110].…”

“…L. lactis with cell surface expression of InlA and/or FnBPA has been used to deliver DNA plasmids to intestinal epithelial cells. Delivery of β-lactoglobulin antigen DNA resulted in an increase of β-lactoglobulin within the intestinal lumen, increased Th1 and Th2 cytokine responses, and increased serum and bronchoalveolar fluid IgG and serum IgA (after intranasal delivery of DNA coding for Mycobacterium tuberculosis Ag85A) [98][99][100][101]. The use of InlA and FnBPA to deliver antigens to epithelial cells may be an effective mucosal vaccine strategy, especially if the desire is to deliver antigen via a eukaryotic expression plasmid (DNA vaccine).…”

Genetic Engineering of Lactococcus lactis Co-producing Antigen and the Mucosal Adjuvant 3′ 5′- cyclic di Adenosine Monophosphate (c-di-AMP) as a Design Strategy to Develop a Mucosal Vaccine Prototype

“…The potential biotechnological applications of this microorganism in the pharmaceutical drug production and the spectrum of possibilities it offers constitutes nowadays one of the most striking reasons for the investigation on L. lactis genetic manipulation ( Cano-Garrido et al, 2015 ). In particular, the use of L. lactis as a live non-invasive mucosal vaccine seems a promising alternative due to their GRAS (Generally Recognized As Safe) status ( Miyoshi et al, 2002 ; Bermudez-Humaran et al, 2003 ; Foligne et al, 2007 ; Wells and Mercenier, 2008 ; Cano-Garrido et al, 2015 ; Kim et al, 2015 ; Mancha-Agresti et al, 2017 ).…”

“…L. lactis has been successfully employed to produce specific viral and bacterial antigens to cope infections or non-antigenic immunomodulatory proteins like cytokines or proteases to control infections or more complex inflammatory diseases such as the inflammatory bowel disease ( Miyoshi et al, 2002 ; Bermudez-Humaran et al, 2003 ; Foligne et al, 2007 ; Wells and Mercenier, 2008 ; Marelli et al, 2011 ; Cano-Garrido et al, 2015 ; Kim et al, 2015 ; Mancha-Agresti et al, 2017 ). Most importantly, it has been used for the expression and delivery of heterologous antigens to develop oral and mucosal vaccines ( Wells and Mercenier, 2008 ; Cano-Garrido et al, 2015 ).…”