SPA14 liposomes combining saponin with fully synthetic TLR4 agonist provide adjuvanticity to hCMV vaccine candidate.

In the aim of designing and developing a novel saponin-based adjuvant system, we combined the QS21 saponin with low microgram amounts of the fully synthetic TLR4 agonist, E6020, in cholesterol-containing liposomes. The resulting adjuvant system, termed SPA14, appeared as a long-term stable and homogeneous suspension of mostly unilamellar and a few multilamellar vesicles, with an average hydrodynamic diameter of 93 nm, when formulated in citrate buffer at pH 6.0-6.

The impact of nucleoside base modification in mRNA vaccine is influenced by the chemistry of its lipid nanoparticle delivery system.

The use of modified nucleosides is an important approach to mitigate the intrinsic immunostimulatory activity of exogenous mRNA and to increase its translation for mRNA therapeutic applications. However, for vaccine applications, the intrinsic immunostimulatory nature of unmodified mRNA could help induce productive immunity. Additionally, the ionizable lipid nanoparticles (LNPs) used to deliver mRNA vaccines can possess immunostimulatory properties that may influence the impact of nucleoside modification.

Anti-staphylococcus aureus adaptive immunity is impaired in end-stage renal disease patients on hemodialysis: one-year longitudinal study.

Introduction: Patients with end-stage renal disease (ESRD) display defects in adaptive and innate immunity, increasing susceptibility to infection. () is a major cause of bacteraemia in this population and is associated with increased mortality. More information on the immune response to in these patients is needed to inform effective vaccine development.

An optimized purified inactivated Zika vaccine provides sustained immunogenicity and protection in cynomolgus macaques.

The recent spread of Zika virus (ZIKV) through the Americas and Caribbean and its devastating consequences for pregnant women and their babies have driven the search for a safe and efficacious ZIKV vaccine. Among the vaccine candidates, a first-generation ZIKV purified inactivated vaccine (ZPIV), adjuvanted with aluminum hydroxide, developed by the Walter Reed Army Institute of Research (WRAIR), has elicited high seroconversion rates in participants in three phase-I clinical trials. In collaboration with the WRAIR, Sanofi Pasteur (SP) optimized the production scale, culture and purification conditions, and increased the regulatory compliance, both of which are critical for clinical development and licensure of this vaccine.

Glycosylation of Staphylococcus aureus cell wall teichoic acid is influenced by environmental conditions.

Wall teichoic acid (WTA) are major constituents of Staphylococcus aureus (S. aureus) cell envelopes with important roles in the bacteria's physiology, resistance to antimicrobial molecules, host interaction, virulence and biofilm formation. They consist of ribitol phosphate repeat units in which the ribitol residue is substituted with D-alanine (D-Ala) and N-acetyl-D-glucosamine (GlcNAc).

Impact of Anesthesia Protocols on In Vivo Bioluminescent Bacteria Imaging Results.

Infectious murine models greatly benefit from optical imaging using bioluminescent bacteria to non-invasively and repeatedly follow in vivo bacterial infection. In this context, one of the most critical parameters is the bioluminescence sensitivity to reliably detect the smallest number of bacteria. Another critical point is the anesthetic approaches that have been demonstrated to impact the bioluminescence flux emission in studies with luciferase-transfected tumor cells.

Production, secretion and purification of a correctly folded staphylococcal antigen in Lactococcus lactis.

Background: Lactococcus lactis, a lactic acid bacterium traditionally used to ferment milk and manufacture cheeses, is also, in the biotechnology field, an interesting host to produce proteins of medical interest, as it is "Generally Recognized As Safe". Furthermore, as L. lactis naturally secretes only one major endogenous protein (Usp45), the secretion of heterologous proteins in this species facilitates their purification from a protein-poor culture medium.

Improvement of immunogenicity of meningococcal lipooligosaccharide by coformulation with lipidated transferrin-binding protein B in liposomes: implications for vaccine development.

Among various meningococcal antigens, lipooligosaccharide (LOS) and recombinant lipidated transferrin-binding protein B (rlip-TbpB) are considered to be putative vaccine candidates against group B Neisseria meningitidis. In the present work, we report the development of a new liposome-based vaccine formulation containing both rlip-TbpB and L8 LOS. The endotoxic activity of the liposomal LOS was evaluated in vitro using the Limulus Amebocyte Lysate assay and compared to the endotoxic activity of free LOS.

CD4 T cell antigens from Staphylococcus aureus Newman strain identified following immunization with heat-killed bacteria.

Staphylococcus aureus is a commensal bacterium associated with the skin and mucosal surfaces of humans and animals that can also cause chronic infection. The emergence of antibiotic-resistant strains such as methicillin-resistant S. aureus (MRSA) and strains causing chronic intramammary infections (IMI) in cows results in severe human and livestock infections.

Genetic and structural characterization of L11 lipooligosaccharide from Neisseria meningitidis serogroup A strains.

The lipooligosaccharide (LOS) of immunotype L11 is unique within serogroup A meningococci. In order to resolve its molecular structure, we conducted LOS genotyping by PCR analysis of genes responsible for alpha-chain sugar addition (lgtA, -B, -C, -E, -H, and -F) and inner core substituents (lgtG, lpt-3, and lpt-6). For this study, we selected seven strains belonging to subgroup III, a major clonal complex responsible for meningococcal meningitis epidemics in Africa.

Distribution of transferrin binding protein B gene (tbpB) variants among Neisseria species.

Background: Transferrin binding protein B (tbpB), an outer membrane lipoprotein, is required for the acquisition of iron from human transferrin. Two tbpB families have been documented in Neisseria meningitidis: an isotype I tbpB gene of 1.8 kb and an isotype II tbpB gene of 2.

Molecular characterization of Clostridium tetani strains by pulsed-field gel electrophoresis and colony PCR.

Pulsed-field gel electrophoresis and PCR were applied for the first time to the molecular characterization of Clostridium tetani. Among five strains tested, one (CN1339) turned out to contain a mixture of two genetically different clones and two (D11 and G761) to contain bacteria differing by the presence or absence of the 74-kb plasmid harboring the tetX gene.

Helicobacter pylori infection induces interleukin-8 receptor expression in the human gastric epithelium.

The gastric pathogen Helicobacter pylori is known to activate multiple proinflammatory signaling pathways in epithelial cells. In this study, we addressed the question of whether expression of the interleukin-8 receptors IL-8RA (CXCR1) and IL-8RB (CXCR2) is upregulated in H. pylori-infected human gastric biopsy samples.

Gastric mucosal recognition of Helicobacter pylori is independent of Toll-like receptor 4.

Little is known about the interactions between Helicobacter pylori, which specializes in colonizing the mucin layer that covers the gastric mucosa, and primary gastric epithelial cells. The expression pattern of Toll-like receptors (TLRs) in primary gastric epithelial cells and cell lines was compared. Primary cells did not express TLR4, whereas all cell lines expressed a nonsignaling form of TLR4.

Assessment of Helicobacter pylori gene expression within mouse and human gastric mucosae by real-time reverse transcriptase PCR.

Despite increasing knowledge on the biology of Helicobacter pylori, little is known about the expression pattern of its genome during infection. While mouse models of infection have been widely used for the screening of protective antigens, the reliability of the mouse model for gene expression analysis has not been assessed. In an attempt to address this question, we have developed a quantitative reverse transcriptase PCR (RT-PCR) that allowed the detection of minute amounts of mRNA within the gastric mucosa.

Formulations of single or multiple H. pylori antigens with DC Chol adjuvant induce protection by the systemic route in mice. Optimal prophylactic combinations are different from therapeutic ones.

The ability to induce a protective response against Helicobacter pylori infection has been investigated by systemic immunization of mice with urease formulated with the cationic lipid DC Chol. This compound acts both as a formulating agent and as an adjuvant and induces a balanced Th1/Th2 response shown to be more effective for protection in our previous studies. Urease-DC Chol induced a significant protection in prophylaxis but not in therapeutic immunization.

Allelic diversity of the two transferrin binding protein B gene isotypes among a collection of Neisseria meningitidis strains representative of serogroup B disease: implication for the composition of a recombinant TbpB-based vaccine.

The distribution of the two isotypes of tbpB in a collection of 108 serogroup B meningococcal strains belonging to the four major clonal groups associated with epidemic and hyperendemic disease (the ET-37 complex, the ET-5 complex, lineage III, and cluster A4) was determined. Isotype I strains (with a 1.8-kb tbpB gene) was less represented than isotype II strains (19.

Comparison between targeted and untargeted systemic immunizations with adjuvanted urease to cure Helicobacter pylori infection in mice.

Outbred OF1 mice infected in a first step with a mouse-adapted Helicobacter pylori strain were immunized in a second step by systemic or mucosal routes: systemic immunizations were performed subcutaneously with adjuvanted urease either in the infra or supra-diaphragmatic region of the body, while mucosal immunization was done with urease in the presence of E. coli heat Labile toxin. Mucosal and subcutaneous immunizations induced in infected mice a significant reduction in bacterial density whatever the site of injection but complete eradication was preferentially observed in mice immunized subcutaneously in the back.

Systemic immunization with urease protects mice against Helicobacter pylori infection.

The ability of systemic immunization to induce protection against Helicobacter pylori infection has been evaluated in a mouse model. It was observed that if appropriate formulations and adjuvants were used such immunization elicited in outbred Swiss mice levels of protection similar or better than those induced by the oral route in the presence of cholera toxin or Escherichia coli heat labile toxin. Recombinant urease mixed with adjuvants, which induced strong Th1 and Th2 responses elicited better protection than urease mixed with adjuvants which induced a predominant Th2 type response only.

Characterization of genetic exchanges between various highly divergent tbpBs, having occurred in Neisseria meningitidis.

Transferrin-binding protein B (TbpB) from Neisseria is an outer membrane-associated extracellular protein involved in iron capture during bacterial infection. The tbpB genes display extensive divergences throughout the open reading frame (ORF) that have presumably been selected under the pressure of the immune system. Early studies suggested that they could possibly constitute two distantly related groups of genes (sharing less than 57% identical nt).

Heterogeneity of tbpB, the transferrin-binding protein B gene, among serogroup B Neisseria meningitidis strains of the ET-5 complex.

ET-5 complex strains of Neisseria meningitidis were traced intercontinentally and have been causing hyperendemic meningitis on a worldwide scale. In an attempt to develop a fully broad cross-reactive transferrin-binding protein B (TbpB)-based vaccine, we undertook to assess the extent of variability of TbpB proteins among strains of this epidemiological complex. For this purpose, a PCR-based method was developed to study the heterogeneity of the tbpB genes from 31 serogroup B N.

Evaluation of recombinant transferrin-binding protein B variants from Neisseria meningitidis for their ability to induce cross-reactive and bactericidal antibodies against a genetically diverse collection of serogroup B strains.

Transferrin-binding protein B (TbpB) is a surface-exposed protein, variable among strains of Neisseria meningitidis, that has been considered as a vaccine candidate. To define a TbpB molecule that would give rise to broadly cross-reactive antibodies with TbpB of many strains, specific antisera were produced against three recombinant TbpB variants from strain M982: one corresponding to the full-length TbpB; one in which stretches of amino acids located in the central part of the molecule, described as hypervariable, have been deleted; and one corresponding to the N-terminal half of the molecule, described as the human transferrin binding domain. The reactivity of these antisera against 58 serogroup B strains with a 2.

Variable sequences in a mosaic-like domain of meningococcal tbp2 encode immunoreactive epitopes.

Transferrin-binding proteins from Neisseria meningitidis vary among different isolates. We have identified and studied a hypervariable region adjacent to the carboxyl-end of the transferrin-binding domain of the Tbp2 molecule. The tbp2 genes from six strains of N.

Diversity of the transferrin-binding protein Tbp2 of Neisseria meningitidis.

In order to investigate the genetic basis for the observed polymorphism amongst meningococcal transferrin-binding proteins, Tbp2, the corresponding genes of different Neisseria meningitidis strains were cloned and sequenced. Comparison of the deduced amino acid (aa) sequences indicated that the Tbp2 were 76.6 to 81.