Lactococcus lactis carrying a DNA vaccine coding for the ESAT-6 antigen increases IL-17 cytokine secretion and boosts the BCG vaccine immune response.

AIMS: A regimen utilizing Bacille Calmette-Guerin (BCG) and another vaccine system as a booster may represent a promising strategy for the development of an efficient tuberculosis vaccine for adults. In a previous work, we confirmed the ability of Lactococcus lactis fibronectin-binding protein A (FnBPA+) (pValac:ESAT-6), a live mucosal DNA vaccine, to produce a specific immune response in mice after oral immunization. In this study, we examined the immunogenicity of this strain as a booster for the BCG vaccine in mice. METHODS AND RESULTS: After immunization, cytokine and immunoglobulin profiles were measured. The BCG prime L. lactis FnBPA+ (pValac:ESAT-6) boost group was the most responsive group, with a significant increase in splenic pro-inflammatory cytokines IL-17, IFN-γ, IL-6 and TNF-α compared with the negative control. CONCLUSIONS: Based on the results obtained here, we demonstrated that L. lactis FnBPA+ (pValac:ESAT-6) was able to increase the BCG vaccine general immune response. SIGNIFICANCE AND IMPACT OF THE STUDY: This work is of great scientific and social importance because it represents the first step towards the development of a booster to the BCG vaccine using L. lactis as a DNA delivery system.

Optimization of gene delivery to HEK293T cells by microporation using a central composite design methodology.

Microporation is an efficient method for delivering plasmid DNA molecules into cultured cells. Herein, we present the optimization of gene delivery by microporation using a Central Composite Design methodology. It was given relevance not only to the transfection efficiency but also to the cell recovery. Different amounts of DNA (1 and 3 µg) mainly affected cell viabilities and cell recoveries, which decrease from 93 to 76% and from 47 to 25% respectively, when higher DNA quantity is used. With this work we suggest an easy methodology to improve transfection of mammalian cells underlining the feasibility to achieve 60% of gene delivery efficiencies whilst recovering 50% of cells, with 90% of viability.