A unique, newly discovered four-member protein family involved in extracellular fatty acid binding in Yarrowia lipolytica.

BACKGROUND: Yarrowia lipolytica, a nonconventional oleaginous yeast species, has attracted attention due to its high lipid degradation and accumulation capacities. Y. lipolytica is used as a chassis for the production of usual and unusual lipids and lipid derivatives. While the genes involved in the intracellular transport and activation of fatty acids in different cellular compartments have been characterized, no genes involved in fatty acid transport from the extracellular medium into the cell have been identified thus far. In this study, we identified secreted proteins involved in extracellular fatty acid binding. RESULTS: Recent analysis of the Y. lipolytica secretome led to the identification of a multigene family that encodes four secreted proteins, preliminarily named UP1 to UP4. These proteins were efficiently overexpressed individually in wild-type and multideletant strain (Q4: Δup1Δup2Δup3Δup4) backgrounds. Phenotypic analysis demonstrated the involvement of these proteins in the binding of extracellular fatty acids. Additionally, gene deletion and overexpression prevented and promoted sensitivity to octanoic acid (C8) toxicity, respectively. The results suggested binding is dependent on aliphatic chain length and fatty acid concentration. 3D structure modeling supports the proteins' role in fatty acid assimilation at the molecular level. CONCLUSIONS: We discovered a family of extracellular-fatty-acid-binding proteins in Y. lipolytica and have proposed to name its members eFbp1 to eFbp4. The exact mode of eFbps action remains to be deciphered individually and synergistically; nevertheless, it is expected that the proteins will have applications in lipid biotechnology, such as improving fatty acid production and/or bioconversion.

Efficient expression vectors and host strain for the production of recombinant proteins by Yarrowia lipolytica in process conditions.

BACKGROUND: The oleaginous yeast Yarrowia lipolytica is increasingly used as an alternative cell factory for the production of recombinant proteins. Recently, regulated promoters from genes EYK1 and EYD1, encoding an erythrulose kinase and an erythritol dehydrogenase, respectively, have been identified and characterized in this yeast. Hybrid promoters up-regulated by polyols such as erythritol and erythrulose have been developed based on tandem copies of upstream activating sequences from EYK1 (UAS1EYK1) and XPR2 (encoding extracellular protease, UAS1XPR2) promoters. RESULTS: The strength of native (pEYD1) and engineered promoters (pEYK1-3AB and pHU8EYK) was compared using the extracellular lipase CalB from Candida antarctica as a model protein and a novel dedicated host strain. This latter is engineered in polyol metabolism and allows targeted chromosomal integration. In process conditions, engineered promoters pEYK1-3AB and pHU8EYK yielded 2.8 and 2.5-fold higher protein productivity, respectively, as compared to the reference pTEF promoter. We also demonstrated the possibility of multicopy integration in the newly developed host strain. In batch bioreactor, the CalB multi-copy strain RIY406 led to a 1.6 fold increased lipase productivity (45,125 U mL-1) within 24 h as compared to the mono-copy strain. CONCLUSIONS: The expression system described herein appears promising for recombinant extracellular protein production in Y. lipolytica.

Impact of a vaccination programme in children vaccinated with ProQuad, and ProQuad-specific effectiveness against varicella in the Veneto region of Italy.

BACKGROUND: Monovalent varicella vaccines have been available in the Veneto Region of Italy since 2004. In 2006, a single vaccine dose was added to the immunisation calendar for children aged 14 months. ProQuad®, a quadrivalent measles-mumps-rubella-varicella vaccine, was introduced in May 2007 and used, among other varicella vaccines, until October 2008. This study aimed to evaluate the effectiveness of a single dose of ProQuad, and the population impact of a vaccination program (VP) against varicella of any severity in children who received a first dose of ProQuad at 14 months of age in the Veneto Region, METHODS: All children born in 2006/2007, i.e., eligible for varicella vaccination after ProQuad was introduced, were retrospectively followed through individual-level data linkage between the Pedianet database (varicella cases) and the Regional Immunization Database (vaccination status). The direct effectiveness of ProQuad was estimated as the incidence rate of varicella in ProQuad-vaccinated children aged < 6 years compared to children with no varicella vaccination from the same birth cohort. The impact of the VP on varicella was measured by comparing children eligible for the VP to an unvaccinated historical cohort from 1997/1998. The vaccine impact measures were: total effect (the combined effect of ProQuad vaccination and being covered by the Veneto VP); indirect effect (the effect of the VP on unvaccinated individuals); and overall effect (the effect of the VP on varicella in the entire population of the Veneto Region, regardless of their vaccination status). RESULTS: The adjusted direct effectiveness of ProQuad was 94%. The vaccine impact measures total, indirect, and overall effect were 97%, 43%, and 90%, respectively. CONCLUSIONS: These are the first results on the effectiveness and impact of ProQuad against varicella; data confirmed its high effectiveness, based on immunological correlates for protection. Direct effectiveness is our only ProQuad-specific measure; all impact measures refer at least partially to the VP and should be interpreted in the context of high vaccine coverage and the use of various varicella vaccines in this region. The Veneto Region offered a unique opportunity for this study due to an individual data linkage between Pedianet and the Regional Immunization database.

Enhancing erythritol productivity in Yarrowia lipolytica using metabolic engineering.

Erythritol (1,2,3,4-butanetetrol) is a four-carbon sugar alcohol with sweetening properties that is used by the agrofood industry as a food additive. In this study, we demonstrated that metabolic engineering can be used to improve the production of erythritol from glycerol in the yeast Yarrowia lipolytica. The best results were obtained using a mutant that overexpressed GUT1 and TKL1, which encode a glycerol kinase and a transketolase, respectively, and in which EYK1, which encodes erythrulose kinase, was disrupted; the latter enzyme is involved in an early step of erythritol catabolism. In this strain, erythritol productivity was 75% higher than in the wild type; furthermore, the culturing time needed to achieve maximum concentration was reduced by 40%. An additional advantage is that the strain was unable to consume the erythritol it had created, further increasing the process's efficiency. The erythritol productivity values we obtained here are among the highest reported thus far.

Sugar versus fat: elimination of glycogen storage improves lipid accumulation in Yarrowia lipolytica.

Triacylglycerol (TAG) and glycogen are the two major metabolites for carbon storage in most eukaryotic organisms. We investigated the glycogen metabolism of the oleaginous Yarrowia lipolytica and found that this yeast accumulates up to 16% glycogen in its biomass. Assuming that elimination of glycogen synthesis would result in an improvement of lipid accumulation, we characterized and deleted the single gene coding for glycogen synthase, YlGSY1. The mutant was grown under lipogenic conditions with glucose and glycerol as substrates and we obtained up to 60% improvement in TAG accumulation compared to the wild-type strain. Additionally, YlGSY1 was deleted in a background that was already engineered for high lipid accumulation. In this obese background, TAG accumulation was also further increased. The highest lipid content of 52% was found after 3 days of cultivation in nitrogen-limited glycerol medium. Furthermore, we constructed mutants of Y. lipolytica and Saccharomyces cerevisiae that are deleted for both glycogen and TAG synthesis, demonstrating that the ability to store carbon is not essential. Overall, this work showed that glycogen synthesis is a competing pathway for TAG accumulation in oleaginous yeasts and that deletion of the glycogen synthase has beneficial effects on neutral lipid storage.

Droplet-based microfluidic high-throughput screening of heterologous enzymes secreted by the yeast Yarrowia lipolytica.

BACKGROUND: Droplet-based microfluidics is becoming an increasingly attractive alternative to microtiter plate techniques for enzymatic high-throughput screening (HTS), especially for exploring large diversities with lower time and cost footprint. In this case, the assayed enzyme has to be accessible to the substrate within the water-in-oil droplet by being ideally extracellular or displayed at the cell surface. However, most of the enzymes screened to date are expressed within the cytoplasm of Escherichia coli cells, which means that a lysis step must take place inside the droplets for enzyme activity to be assayed. Here, we take advantage of the excellent secretion abilities of the yeast Yarrowia lipolytica to describe a highly efficient expression system particularly suitable for the droplet-based microfluidic HTS. RESULTS: Five hydrolytic genes from Aspergillus niger genome were chosen and the corresponding five Yarrowia lipolytica producing strains were constructed. Each enzyme (endo-ß-1,4-xylanase B and C; 1,4-ß-cellobiohydrolase A; endoglucanase A; aspartic protease) was successfully overexpressed and secreted in an active form in the crude supernatant. A droplet-based microfluidic HTS system was developed to (a) encapsulate single yeast cells; (b) grow yeast in droplets; (c) inject the relevant enzymatic substrate; (d) incubate droplets on chip; (e) detect enzymatic activity; and (f) sort droplets based on enzymatic activity. Combining this integrated microfluidic platform with gene expression in Y. lipolytica results in remarkably low variability in the enzymatic activity at the single cell level within a given monoclonal population (<5%). Xylanase, cellobiohydrolase and protease activities were successfully assayed using this system. We then used the system to screen for thermostable variants of endo-ß-1,4-xylanase C in error-prone PCR libraries. Variants displaying higher thermostable xylanase activities compared to the wild-type were isolated (up to 4.7-fold improvement). CONCLUSIONS: Yarrowia lipolytica was used to express fungal genes encoding hydrolytic enzymes of interest. We developed a successful droplet-based microfluidic platform for the high-throughput screening (105 strains/h) of Y. lipolytica based on enzyme secretion and activity. This approach provides highly efficient tools for the HTS of recombinant enzymatic activities. This should be extremely useful for discovering new biocatalysts via directed evolution or protein engineering approaches and should lead to major advances in microbial cell factory development.

New inducible promoter for gene expression and synthetic biology in Yarrowia lipolytica.

BACKGROUND: The oleaginous yeast Yarrowia lipolytica is increasingly used as alternative cell factory for the production of recombinant proteins. At present, several promoters with different strengths have been developed based either on the constitutive pTEF promoter or on oleic acid inducible promoters such as pPOX2 and pLIP2. Although these promoters are highly efficient, there is still a lack of versatile inducible promoters for gene expression in Y. lipolytica. RESULTS: We have isolated and characterized the promoter of the EYK1 gene coding for an erythrulose kinase. pEYK1 induction was found to be impaired in media supplemented with glucose and glycerol, while the presence of erythritol and erythrulose strongly increased the promoter induction level. Promoter characterization and mutagenesis allowed the identification of the upstream activating sequence UAS1EYK1. New hybrid promoters containing tandem repeats of either UAS1XPR2 or UAS1EYK1 were developed showing higher expression levels than the native pEYK1 promoter. Furthermore, promoter strength was improved in a strain carrying a deletion in the EYK1 gene, allowing thus the utilization of erythritol and erythrulose as free inducer. CONCLUSIONS: Novel tunable and regulated promoters with applications in the field of heterologous protein production, metabolic engineering, and synthetic biology have been developed, thus filling the gap of the absence of versatile inducible promoter in the yeast Y. lipolytica.

Using a vector pool containing variable-strength promoters to optimize protein production in Yarrowia lipolytica.

BACKGROUND: The yeast Yarrowia lipolytica is an increasingly common biofactory. To enhance protein expression, several promoters have been developed, including the constitutive TEF promoter, the inducible POX2 promotor, and the hybrid hp4d promoter. Recently, new hp4d-inspired promoters have been created that couple various numbers of UAS1 tandem elements with the minimal LEU2 promoter or the TEF promoter. Three different protein-secretion signaling sequences can be used: preLip2, preXpr2, and preSuc2. RESULTS: To our knowledge, our study is the first to use a set of vectors with promoters of variable strength to produce proteins of industrial interest. We used the more conventional TEF and hp4d promoters along with five new hybrid promoters: 2UAS1-pTEF, 3UAS1-pTEF, 4UAS1-pTEF, 8UAS1-pTEF, and hp8d. We compared the production of RedStar2, glucoamylase, and xylanase C when strains were grown on three media. As expected, levels of RedStar2 and glucoamylase were greatest in the strain with the 8UAS1-pTEF promoter, which was stronger. However, surprisingly, the 2UAS1-pTEF promoter was associated with the greatest xylanase C production and activity. This finding underscored that stronger promoters are not always better when it comes to protein production. We therefore developed a method for easily identifying the best promoter for a given protein of interest. In this gateway method, genes for YFP and α-amylase were transferred into a pool of vectors containing different promoters and gene expression was then analyzed. We observed that, in most cases, protein production and activity were correlated with promoter strength, although this pattern was protein dependent. CONCLUSIONS: Protein expression depends on more than just promoter strength. Indeed, promoter suitability appears to be protein dependent; in some cases, optimal expression and activity was obtained using a weaker promoter. We showed that using a vector pool containing promoters of variable strength can be a powerful tool for rapidly identifying the best producer for a given protein of interest.

Insights into the Genomic and Phenotypic Landscape of the Oleaginous Yeast Yarrowia lipolytica.

Although Yarrowia lipolytica is a model yeast for the study of lipid metabolism, its diversity is poorly known, as studies generally consider only a few standard laboratory strains. To extend our knowledge of this biotechnological workhorse, we investigated the genomic and phenotypic diversity of 56 natural isolates. Y. lipolytica is classified into five clades with no correlation between clade membership and geographic or ecological origin. A low genetic diversity (π = 0.0017) and a pan-genome (6528 genes) barely different from the core genome (6315 genes) suggest Y. lipolytica is a recently evolving species. Large segmental duplications were detected, totaling 892 genes. With three new LTR-retrotransposons of the Gypsy family (Tyl4, Tyl9, and Tyl10), the transposable element content of genomes appeared diversified but still low (from 0.36% to 3.62%). We quantified 34 traits with substantial phenotypic diversity, but genome-wide association studies failed to evidence any associations. Instead, we investigated known genes and found four mutational events leading to XPR2 protease inactivation. Regarding lipid metabolism, most high-impact mutations were found in family-belonging genes, such as ALK or LIP, and therefore had a low phenotypic impact, suggesting that the huge diversity of lipid synthesis and accumulation is multifactorial or due to complex regulations.

Impact of the metabolic activity of Streptococcus thermophilus on the colon epithelium of gnotobiotic rats.

The thermophilic lactic acid bacterium Streptococcus thermophilus is widely and traditionally used in the dairy industry. Despite the vast level of consumption of S. thermophilus through yogurt or probiotic functional food, very few data are available about its physiology in the gastrointestinal tract (GIT). The objective of the present work was to explore both the metabolic activity and host response of S. thermophilus in vivo. Our study profiles the protein expression of S. thermophilus after its adaptation to the GIT of gnotobiotic rats and describes the impact of S. thermophilus colonization on the colonic epithelium. S. thermophilus colonized progressively the GIT of germ-free rats to reach a stable population in 30 days (10(8) cfu/g of feces). This progressive colonization suggested that S. thermophilus undergoes an adaptation process within GIT. Indeed, we showed that the main response of S. thermophilus in the rat's GIT was the massive induction of the glycolysis pathway, leading to formation of lactate in the cecum. At the level of the colonic epithelium, the abundance of monocarboxylic acid transporter mRNAs (SLC16A1 and SLC5A8) and a protein involved in the cell cycle arrest (p27(kip1)) increased in the presence of S. thermophilus compared with germ-free rats. Based on different mono-associated rats harboring two different strains of S. thermophilus (LMD-9 or LMG18311) or weak lactate-producing commensal bacteria (Bacteroides thetaiotaomicron and Ruminococcus gnavus), we propose that lactate could be a signal produced by S. thermophilus and modulating the colon epithelium.

Immunogenicity and safety of ZOSTAVAX(®) approaching expiry potency in individuals aged ≥50 years.

BACKGROUND: Age is a major risk factor for herpes zoster (HZ) and its potential long-term complication post-herpetic neuralgia (PHN). Due to the significant burden of HZ and PHN on patients' quality of life, it is vital that effective and well-tolerated vaccines are available to prevent HZ in older adults. ZOSTAVAX(®) vaccine was developed to prevent HZ and PHN in individuals ≥50 years (y) of age, and its clinical efficacy and safety have been demonstrated. AIMS AND METHODS: This phase 4, open-label, multicenter study was undertaken to assess the immunogenicity and safety of a single dose of ZOSTAVAX (refrigerator-stable formulation) given within 6 mo of its expiry date in individuals ≥50 y of age. The geometric mean fold rise (GMFR) from pre-vaccination to 4 weeks post-vaccination in varicella zoster virus (VZV) antibody titers was calculated. An acceptable antibody response was defined as a lower 95% confidence interval (CI) of GMFR > 1.4. Solicited and unsolicited injection-site reactions and systemic adverse events were recorded. RESULTS: The GMFR in VZV antibody titers was 3.1 (95% CI: 2.6, 3.8), satisfying the criterion for an acceptable VZV antibody response to ZOSTAVAX (minimum requirement: 1.4 GMFR). An acceptable rise in VZV antibody titers was observed in individuals of 50-59 y of age (GMFR 3.9; 95% CI: 2.9, 5.1) and in those ≥60 y of age (GMFR 2.5; 95% CI: 1.9, 3.2). ZOSTAVAX was well tolerated; no serious adverse events were reported. CONCLUSION: ZOSTAVAX elicits an acceptable immune response in immunocompetent individuals ≥50 y of age when stored as directed and administered during the 6 mo prior to expiration.

Evaluation of non-inferiority of intradermal versus adjuvanted seasonal influenza vaccine using two serological techniques: a randomised comparative study.

BACKGROUND: Although seasonal influenza vaccine is effective in the elderly, immune responses to vaccination are lower in the elderly than in younger adults. Strategies to optimise responses to vaccination in the elderly include using an adjuvanted vaccine or using an intradermal vaccination route. The immunogenicity of an intradermal seasonal influenza vaccine was compared with that of an adjuvanted vaccine in the elderly. METHODS: Elderly volunteers (age > or = 65 years) were randomised to receive a single dose of trivalent seasonal influenza vaccine: either a split-virion vaccine containing 15 microg haemagglutinin [HA]/strain/0.1-ml dose administered intradermally, or a subunit vaccine (15 microg HA/strain/0.5-ml dose) adjuvanted with MF59C.1 and administered intramuscularly. Blood samples were taken before and 21 +/- 3 days post-vaccination. Anti-HA antibody titres were assessed using haemagglutination inhibition (HI) and single radial haemolysis (SRH) methods. We aimed to show that the intradermal vaccine was non-inferior to the adjuvanted vaccine. RESULTS: A total of 795 participants were enrolled (intradermal vaccine n = 398; adjuvanted vaccine n = 397). Non-inferiority of the intradermal vaccine was demonstrated for the A/H1N1 and B strains, but not for the A/H3N2 strain (upper bound of the 95% CI = 1.53) using the HI method, and for all three strains by the SRH method. A post-hoc analysis of covariance to adjust for baseline antibody titres demonstrated the non-inferiority of the intradermal vaccine by HI and SRH methods for all three strains. Both vaccines were, in general, well tolerated; the incidence of injection-site reactions was higher for the intradermal (70.1%) than the adjuvanted vaccine (33.8%) but these reactions were mild and of short duration. CONCLUSIONS: The immunogenicity and safety of the intradermal seasonal influenza vaccine in the elderly was comparable with that of the adjuvanted vaccine. Intradermal vaccination to target the immune properties of the skin appears to be an appropriate strategy to address the challenge of declining immune responses in the elderly. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00554333.

Randomized clinical trial of DTaP5-HB-IPV-Hib vaccine administered concomitantly with meningococcal serogroup C conjugate vaccines during the primary infant series.

BACKGROUND: Concomitant administration of vaccines simplifies delivery. DTaP5-HB-IPV-Hib is a fully liquid, combination vaccine against 6 diseases. This study evaluated the compatibility of DTaP5-HB-IPV-Hib with 2 different meningococcus group C conjugate (MCC) vaccines in infants. METHODS: In a phase 3, open-label study, 284 healthy infants from 11 UK centres received DTaP5-HB-IPV-Hib at age 2, 3, and 4 months; 13-valent pneumococcal conjugate vaccine (PCV13) at 2 and 4 months; a Haemophilus influenzae type b (Hib)-MCC vaccine and a measles/mumps/rubella vaccine at 12 months. Participants were randomised 1:1 to receive either an MCC-detoxified tetanus toxin vaccine (MCC-TT; n = 141) or an MCC-Corynebacterium diphtheriae CRM197 protein vaccine (MCC-CRM; n = 143) at 3 and 4 months. The primary outcome was seroprotection rate (SPR) to MCC (percent with rabbit complement serum bactericidal antibody titer ≥8). RESULTS: Per protocol analysis, MCC SPRs were 100 and 96.4 one month after the first dose, 100 and 99.1 after the second dose, and 100 and 97.3 after the third (booster) dose of MCC in the MCC-TT and MCC-CRM groups, respectively. One month after all 3 doses of DTaP5-HB-IPV-Hib, immunoglobulin G anti-polyribosylribitol phosphate SPRs (% ≥0.15 µg/mL) were 97.8 in the MCC-TT group and 100 in the MCC-CRM group; anti-hepatitis B antigen SPRs (% ≥10 mIU/mL) were 96.8 and 96.3 in the MCC-TT and MCC-CRM groups, respectively. All participants were seroprotected against diphtheria and tetanus (≥0.01 IU/mL) and poliovirus types 1, 2, and 3 (≥8 dilution), and seroresponse rates to all pertussis antigens were ≥90.4%. Two vaccine-related serious adverse events (transient severe abdominal pain and crying) occurred concomitantly in 1 participant in the MCC-CRM group. Adverse event rates were similar to other studies of DTaP5-HB-IPV-Hib, with pyrexia ≥38 °C in 10.9% of participants following any dose. CONCLUSIONS: DTaP5-HB-IPV-Hib can be effectively used in a 2-, 3-, and 4-month infant priming schedule when given with 2 doses of MCC.

Immunogenicity and safety of concomitant administration of a measles, mumps and rubella vaccine (M-M-RvaxPro) and a varicella vaccine (VARIVAX) by intramuscular or subcutaneous routes at separate injection sites: a randomised clinical trial.

BACKGROUND: When this trial was initiated, the combined measles, mumps and rubella (MMR) vaccine was licensed for subcutaneous administration in all European countries and for intramuscular administration in some countries, whereas varicella vaccine was licensed only for subcutaneous administration. This study evaluated the intramuscular administration of an MMR vaccine (M-M-RvaxPro) and a varicella vaccine (VARIVAX) compared with the subcutaneous route. METHODS: An open-label randomised trial was performed in France and Germany. Healthy children, aged 12 to 18 months, received single injections of M-M-RvaxPro and VARIVAX concomitantly at separate injection sites. Both vaccines were administered either intramuscularly (IM group, n = 374) or subcutaneously (SC group, n = 378). Immunogenicity was assessed before vaccination and 42 days after vaccination. Injection-site erythema, swelling and pain were recorded from days 0 to 4 after vaccination. Body temperature was monitored daily between 0 and 42 days after vaccination. Other adverse events were recorded up to 42 days after vaccination and serious adverse events until the second study visit. RESULTS: Antibody response rates at day 42 in the per-protocol set of children initially seronegative to measles, mumps, rubella or varicella were similar between the IM and SC groups for all four antigens. Response rates were 94 to 96% for measles, 98% for both mumps and rubella and 86 to 88% for varicella. For children initially seronegative to varicella, 99% achieved the seroconversion threshold (antibody concentrations of >or= 1.25 gpELISA units/ml). Erythema and swelling were the most frequently reported injection-site reactions for both vaccines. Most injection-site reactions were of mild intensity or small size (

Immunogenicity and safety of PNEUMOVAX II manufactured by a new process in older adults.

In response to increased demand for the 23-valent pneumococcal vaccine PNEUMOVAX II, a new manufacturing process has been implemented that improves the consistency and increases the scale of production. This double-blind, randomized, clinical study compared the immunogenicity and safety profiles of the new-process PNEUMOVAX II (n = 111) formulated with all 23 new process polysaccharides to the former-process PNEUMOVAX II (n = 109) formulation in adults aged > or =50 years. The primary aim of the study was to compare the post-vaccination geometric mean of antibody titres (GMT) to pneumococcal serotypes 3 and 8 in recipients of new- and former-process PNEUMOVAX II. The post-vaccination GMTs for serotypes 3 and 8 elicited by the new-process PNEUMOVAX II [1.40 (95% confidence interval, 1.21-1.63) and 10.78 (95% CI, 9.10-12.77), respectively] were non-inferior to those elicited by the former-process PNEUMOVAX II [1.24 (95% CI, 1.07-1.43) and 9.72 (95% CI, 8.22-11.50), respectively]. Both PNEUMOVAX II formulations were well tolerated; there were no vaccine-related serious adverse events. A total of 74 (66.7%) subjects in the new-process group and 66 (60.6%) in the former-process group had at least one injection-site reaction or vaccine-related systemic event within 14 days following vaccination. There was a trend for higher incidence of two solicited injection-site reactions (erythmea and induration) and three solicited systemic events (asthenia, chills and body aches) with the new- versus former-process PNEUMOVAX II, but these were mainly of mild intensity and short duration. The new-process PNEUMOVAX(R II thus showed similar immunogenicity to the former-process vaccine for pneumococcal serotypes 3 and 8 and both vaccines were well tolerated in older subjects.

Safety of a refrigerator-stable varicella vaccine (VARIVAX) in healthy 12- to 15-month-old children: A randomized, double-blind, cross-over study.

The safety of a single injection of the refrigerator-stable formulation of varicella vaccine VARIVAX was assessed in a blind, randomized, cross-over trial. Five hundred seven healthy children aged 12 to 15 months received subcutaneous injections of VARIVAX on day 0 and the measles, mumps and rubella vaccine (M-M-R II) on day 42 or M-M-R II on day 0 and VARIVAX on day 42. To maintain blinding, injections were given by a study nurse not involved in safety assessments. M-M-R II acted as a reference to validate the safety assessment, as its safety profile is well known in this age range. Parents or legal guardians recorded adverse events for 42 days following each injection. Solicited injection-site reactions (erythema, swelling, pain) were recorded on days 0 to 4. Other injection-site reactions, daily temperature, rashes and systemic adverse events were recorded on days 0 to 42, and serious adverse events until the final study visit. The safety profile of M-M-R II was consistent with previous reports. Following VARIVAX administration, 47.7% of children had at least one vaccine-related adverse event. Solicited injection-site reactions were reported in 13.0% of children, and 17.2% had at least one other injection-site reaction between days 0 and 42. Most reactions were small (

Blastobotrys adeninivorans and B. raffinosifermentans, two sibling yeast species which accumulate lipids at elevated temperatures and from diverse sugars.

BACKGROUND: In the context of sustainable development, yeast are one class of microorganisms foreseen for the production of oil from diverse renewable feedstocks, in particular those that do not compete with the food supply. However, their use in bulk production, such as for the production of biodiesel, is still not cost effective, partly due to the possible poor use of desired substrates or poor robustness in the practical bioconversion process. We investigated the natural capacity of Blastobotrys adeninivorans, a yeast already used in biotechnology, to store lipids under different conditions. RESULTS: The genotyping of seven strains showed the species to actually be composed of two different groups, one that (including the well-known strain LS3) could be reassigned to Blastobotrys raffinosifermentans. We showed that, under nitrogen limitation, strains of both species can synthesize lipids to over 20% of their dry-cell weight during shake-flask cultivation in glucose or xylose medium for 96 h. In addition, organic acids were excreted into the medium. LS3, our best lipid-producing strain, could also accumulate lipids from exogenous oleic acid, up to 38.1 ± 1.6% of its dry-cell weight, and synthesize lipids from various sugar substrates, up to 36.6 ± 0.5% when growing in cellobiose. Both species, represented by LS3 and CBS 8244T, could grow with little filamentation in the lipogenic medium from 28 to 45 °C and reached lipid titers ranging from 1.76 ± 0.28 to 3.08 ± 0.49 g/L in flasks. Under these conditions, the maximum bioconversion yield (Y FA/S = 0.093 ± 0.017) was obtained with LS3 at 37 °C. The presence of genes for predicted subunits of an ATP citrate lyase in the genome of LS3 reinforces its oleaginous character. CONCLUSIONS: Blastobotrys adeninivorans and B. raffinosifermentans, which are known to be xerotolerant and genetically-tractable, are promising biotechnological yeasts of the Saccharomycotina that could be further developed through genetic engineering for the production of microbial oil. To our knowledge, this is the first report of efficient lipid storage in yeast when cultivated at a temperature above 40 °C. This paves the way to help reducing costs through consolidated bioprocessing.

Concomitant administration of a fully liquid ready-to-use DTaP-IPV-HB-PRP-T hexavalent vaccine with a meningococcal ACWY conjugate vaccine in toddlers.

Invasive meningococcal disease caused by Neisseria meningitidis is a life-threatening disease. Several countries now include meningococcal serogroup C (MenC) conjugate and, more recently, a meningococcal serogroup ACWY conjugate (MenACWY) vaccination in their national immunization schedules. DTaP-IPV-HB-PRP-T is a hexavalent vaccine that provides protection against six diseases. The phase III, open-label, randomised, multicentre study enrolled healthy toddlers who received the DTaP-IPV-HB-PRP-T vaccine (at 2, 3 and 4 months) with or without a MenC vaccine (at 2 and 4 months) in the primary series study. At 12 months of age, 312 toddlers were randomised to receive DTaP-IPV-HB-PRP-T co-administered with MenACWY-TT vaccine (Group A; n = 104); DTaP-IPV-HB-PRP-T vaccine alone (Group B; n = 105); or MenACWY-TT vaccine alone (Group C; n = 103). At 12 months of age, there were no notable differences in terms of antibody persistence for any DTaP-IPV-HB-PRP-T vaccine antigen, whether MenC-TT conjugate vaccine was co-administered or not during the primary series. Following booster vaccination, immune responses to DTaP-IPV-HB-PRP-T and MenACWY-TT vaccines were not affected by co-administration. One month after vaccination, the immune responses elicited by both vaccines were high, whether administered concomitantly or separately. The administration of MenC vaccine during infancy did not preclude the use of a MenACWY-TT vaccine for booster vaccination. Even though the reactogenicity after co-administration was somewhat higher, the results of this study support the concomitant administration of the DTaP-IPV-HB-PRP-T vaccine with a MenACWY-TT conjugate vaccine when given from 12 months of age. The clinical trial registration numbers are: clinicaltrial.gov: NCT01839175; EudraCT: 2012-005547-24.

Immunogenicity and safety of a new hexavalent vaccine (DTaP5-IPV-HB-Hib) administered in a mixed primary series schedule with a pentavalent vaccine (DTaP5-IPV-Hib).

DTaP5-IPV-HB-Hib vaccine is a fully-liquid, combination hexavalent vaccine. This phase III, open-label, multicentre study conducted in Spain, evaluated the immune response to all DTaP5-IPV-HB-Hib antigens when the vaccine was used in a mixed hexa/penta/hexa primary series. Infants (who had received one dose of hepatitis B vaccine at birth) received a mixed schedule including DTaP5-IPV-HB-Hib (PRP-OMP conjugate) at 2 and 6months of age, DTaP5-IPV-Hib at 4months, meningococcal serogroup C conjugate (MCC) vaccine at 2 and 4months, and routine rotavirus and pneumococcal vaccination. One month post-dose 3 of the mixed schedule, response rates were considered acceptable if the lower bound of the two-sided 95% confidence interval around the post-vaccination response rate was >90% for hepatitis B and >80% for Haemophilus influenzae type b (Hib). Secondary immunogenicity objectives included description of the antibody response to all hexavalent antigens one month after completion of the mixed schedule, and to MCC antigen one month after the second MCC dose. The safety profile after each dose of study vaccine was described. Of 385 healthy infants enrolled, 384 completed the study. The primary objective was achieved for both hepatitis B and Hib; the lower bound of the 2-sided 95% CI of the response rates (97.2% and 99.0%, respectively) were greater than the pre-specified acceptability thresholds. One month post-dose 3 of the mixed schedule, all participants were seroprotected against diphtheria, tetanus and polio. The mixed schedule induced a robust immune response to all hexavalent antigens. The co-administration of the hexavalent vaccine in a mixed schedule with MCC vaccine did not reduce the immune response to vaccine antigens. Vaccines were well tolerated. In conclusion, the acceptability of response rates against Hib and hepatitis B were demonstrated one month post-dose 3 of the mixed schedule; robust immune responses against all other hexavalent antigens were observed. clinicaltrial.gov: NCT01839188; EudraCT: 2012-004221-25.

Safety and immune response to a challenge dose of hepatitis B vaccine in healthy children primed 10years earlier with hexavalent vaccines in a 3, 5, 11-month schedule: An open-label, controlled, multicentre trial in Italy.

BACKGROUND AND AIMS: The strategy of vaccinating infants to prevent hepatitis B virus infection in adolescence or adulthood requires durable immunity. This study investigated responses to a challenge dose of monovalent hepatitis B vaccine in children primed with three doses of either Hexavac® or Infanrix hexa® 10years earlier during infancy. METHODS: This open-label, controlled, multicentre study conducted in Italy, enrolled 751 healthy pre-adolescents (aged 11-13years) who were given either Hexavac (n=409) or Infanrix hexa (n=342) at 3, 5 and 11months of life. All participants received a challenge dose of a monovalent hepatitis B vaccine (HBVaxPro® 5µg). The concentrations of antibodies to hepatitis B surface antigen (anti-HBs) were measured before and 1month after the challenge dose. The analysis was descriptive and no formal hypothesis was tested. RESULTS: One month post-challenge, 331 participants in the Hexavac cohort [83.6%, 95% CI: 79.6; 87.1] and 324 in the Infanrix hexa cohort [96.4%, 95% CI: 93.8; 98.1] had anti-HBs concentrations ≥10mIU/mL. Before the challenge dose, an anti-HBs concentration of ≥10mIU/mL was found in 94 children in the Hexavac cohort [23.9%, 95% CI: 19.7; 28.4] and in 232 children in the Infanrix hexa cohort [69%, 95% CI: 63.8; 74.0]. Among children with a pre-challenge anti-HBs concentration of <10mIU/mL, 236 [78.7%, 95% CI: 73.6; 83.2] in the Hexavac cohort and 92 [88.5%, 95% CI: 80.7; 93.9] in the Infanrix hexa cohort achieved protective anti-HBs antibody concentrations. No evidence of active hepatitis B disease was observed in either group, and the HBVaxPro challenge dose was well tolerated. CONCLUSIONS: These data confirm that immune memory persists in a high percentage of children (>80%) at least 10years after a two-dose primary and booster vaccination schedule with a hexavalent vaccine (Hexavac or Infanrix hexa). TRIAL REGISTRATION: EudraCT Number: 2013-001602-28; clinicaltrials.gov: NCT02012998.