title: Recombinant invasive Lactococcus lactis can transfer DNA vaccines either directly to dendritic cells or across an epithelial cell monolayer.
abstract: Lactococcus lactis (L. lactis), a generally regarded as safe (GRAS) bacterium has recently been investigated as a mucosal delivery vehicle for DNA vaccines. Because of its GRAS status, L. lactis represents an attractive alternative to attenuated pathogens. Previous studies showed that eukaryotic expression plasmids could be delivered into intestinal epithelial cells (IECs) by L. lactis, or recombinant invasive strains of L. lactis, leading to heterologous protein expression. Although expression of antigens in IECs might lead to vaccine responses, it would be of interest to know whether uptake of L. lactis DNA vaccines by dendritic cells (DCs) could lead to antigen expression as they are unique in their ability to induce antigen-specific T cell responses. To test this, we incubated mouse bone marrow-derived DCs (BMDCs) with invasive L. lactis strains expressing either Staphylococcus aureus Fibronectin Binding Protein A (LL-FnBPA+), or Listeria monocytogenes mutated Internalin A (LL-mInlA+), both strains carrying a plasmid DNA vaccine (pValac) encoding for the cow milk allergen β-lactoglobulin (BLG). We demonstrated that they can transfect BMDCs, inducing the secretion of the pro-inflammatory cytokine IL-12. We also measured the capacity of strains to invade a polarized monolayer of IECs, mimicking the situation encountered in the gastrointestinal tract. Gentamycin survival assay in these cells showed that LL-mInlA+ is 100 times more invasive than L. lactis. The cross-talk between differentiated IECs, BMDCs and bacteria was also evaluated using an in vitro transwell co-culture model. Co-incubation of strains in this model showed that DCs incubated with LL-mInlA+ containing pValac:BLG could express significant levels of BLG. These results suggest that DCs could sample bacteria containing the DNA vaccine across the epithelial barrier and express the antigen.
authors.affiliation: Laboratório de Genética Celular e Molecular, ICB, UFMG, Belo Horizonte MG, Brazil.
authors.forename: Marcela
authors.initials: M
authors.lastname: de Azevedo
authors.affiliation: Host Microbe Interactomics, Wageningen University, Wageningen, The Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: Meijerink
authors.affiliation: Host Microbe Interactomics, Wageningen University, Wageningen, The Netherlands.
authors.forename: Nico
authors.initials: N
authors.lastname: Taverne
authors.affiliation: Laboratório de Genética Celular e Molecular, ICB, UFMG, Belo Horizonte MG, Brazil.
authors.forename: Vanessa Bastos
authors.initials: VB
authors.lastname: Pereira
authors.affiliation: CERELA-CONICET, San Miguel de Tucumán, Argentina.
authors.forename: Jean Guy
authors.initials: JG
authors.lastname: LeBlanc
authors.affiliation: Laboratório de Genética Celular e Molecular, ICB, UFMG, Belo Horizonte MG, Brazil.
authors.forename: Vasco
authors.initials: V
authors.lastname: Azevedo
authors.affiliation: Laboratório de Genética Celular e Molecular, ICB, UFMG, Belo Horizonte MG, Brazil.
authors.forename: Anderson
authors.initials: A
authors.lastname: Miyoshi
authors.affiliation: INRA, UMR1319 Micalis, Jouy-en-Josas, France; AgroParisTech, UMR Micalis, F-78350 Jouy-en-Josas, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Langella
authors.affiliation: Host Microbe Interactomics, Wageningen University, Wageningen, The Netherlands.
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Wells
authors.affiliation: INRA, UMR1319 Micalis, Jouy-en-Josas, France; AgroParisTech, UMR Micalis, F-78350 Jouy-en-Josas, France. Electronic address: jean-marc.chatel@jouy.inra.fr.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Chatel
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology; D004337:Drug Carriers; D004705:Endocytosis; D004847:Epithelial Cells / Q000276:immunology* / Q000382:microbiology; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D008807:Mice, Inbred BALB C; D019444:Vaccines, DNA / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D004337:Drug Carriers; D019444:Vaccines, DNA; C078635:fibronectin-binding proteins, bacterial; C069761:internalin protein, Bacteria
keywords: DNA delivery; Dendritic cells; Internalization; Lactococcus lactis; Listeria monocytogenes; Mutated internalin A; β-lactoglobulin