Genome sequence of the Klebsiella quasipneumoniae bacteriophage EKq1 with activity against Klebsiella pneumoniae.

We describe the genome of a lytic phage EKq1 isolated on Klebsiella quasipneumoniae, with activity against Klebsiella pneumoniae. EKq1 is an unclassified representative of the class Caudoviricetes, similar to Klebsiella phages VLCpiS8c, phiKp_7-2, and vB_KleS-HSE3. The 48,244-bp genome has a GC content of 56.43% and 63 predicted protein-coding genes.

Interlaboratory comparison of Pseudomonas aeruginosa phage susceptibility testing.

Standardized approaches to phage susceptibility testing (PST) are essential to inform selection of phages for study in patients with bacterial infections. There is no reference standard for assessing bacterial susceptibility to phage. We compared agreement between PST performed at three centers: two centers using a liquid assay standardized between the sites with the third, a plaque assay. Four Pseudomonas aeruginosa phages: PaWRA01ø11 (EPa11), PaWRA01ø39 (EPa39), PaWRA02ø83 (EPa83), PaWRA02ø87 (EPa87), and a cocktail of all four phages were tested against 145 P. aeruginosa isolates. Comparisons were made within measurements at the two sites performing the liquid assay and between these two sites. Agreement was assessed based on coverage probability (CP8), total deviation index, concordance correlation coefficient (CCC), measurement accuracy, and precision. For the liquid assay, there was satisfactory agreement among triplicate measurements made on different days at site 1, and high agreement based on accuracy and precision between duplicate measurements made on the same run at site 2. There was fair accuracy between measurements of the two sites performing the liquid assay, with CCCs below 0.6 for all phages tested. When compared to the plaque assay (performed once at site 3), there was less agreement between results of the liquid and plaque assays than between the two sites performing the liquid assay. Similar findings to the larger group were noted in the subset of 46 P. aeruginosa isolates from cystic fibrosis. Results of this study suggest that reproducibility of PST methods needs further development.

Complete genome sequence of the broad host range Acinetobacter baumannii phage EAb13.

We describe the genome of a lytic phage EAb13 isolated from sewage, with broad activity against multidrug-resistant Acinetobacter baumannii. EAb13 is an unclassified siphovirus. Its genome consists of 82,411 bp, with 40.15% GC content, 126 protein-coding sequences, 1 tRNA, and 2,177 bp-long direct terminal repeats.

Genome Sequence of Staphylococcus aureus Phage ESa2.

We describe the genome of a lytic phage, ESa2, isolated from environmental water and specific for Staphylococcus aureus. ESa2 belongs to the family Herelleviridae and genus Kayvirus. Its genome consists of 141,828 bp, with 30.25% GC content, 253 predicted protein-coding sequences, 3 tRNAs, and 10,130-bp-long terminal repeats.

Safety and microbiological activity of phage therapy in persons with cystic fibrosis colonized with Pseudomonas aeruginosa: study protocol for a phase 1b/2, multicenter, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Bacteriophages (phages) are a promising anti-infective option for human disease. Major gaps remain in understanding their potential utility. METHODS: This is a randomized, placebo-controlled, double-blind study of a single dose of intravenous phage in approximately 72 clinically stable adult cystic fibrosis volunteers recruited from up to 20 US sites with Pseudomonas aeruginosa airway colonization. The single dose of phage consists of a mixture of four anti-pseudomonal phages. Six sentinel participants will be sequentially enrolled with dose escalation of the phage mixture by one log10 beginning with 4 × 107 plaque-forming units in an unblinded stage 1. If no serious adverse events related to the study product are identified, the trial will proceed to a double-blinded stage 2. In stage 2a, 32 participants will be randomly assigned to one of three phage dosages or placebo in a 1:1:1:1 allocation. An interim analysis will be performed to determine the phage dosage with the most favorable safety and microbiological activity profile to inform phage dosing in stage 2b. During stage 2b, up to 32 additional volunteers will be randomized 1:1 to the phage or placebo arm. Primary outcomes include (1) the number of grade 2 or higher treatment-emergent adverse events, (2) change in log10 P. aeruginosa total colony counts in sputum, and (3) the probability of a randomly selected subject having a more favorable outcome ranking if assigned to receive phage therapy versus placebo. Exploratory outcomes include (1) sputum and serum phage pharmacokinetics, (2) the impact of phage on lung function, (3) the proportion of P. aeruginosa isolates susceptible to the phage mixture before and after study product administration, and (4) changes in quality of life. DISCUSSION: This trial will investigate the activity of phages in reducing P. aeruginosa colony counts and provide insights into the safety profile of phage therapy. TRIAL REGISTRATION: ClinicalTrials.gov NCT05453578. Registered on 12 July 2022.

Design of a Bacteriophage Cocktail Active against Shigella Species and Testing of Its Therapeutic Potential in Galleria mellonella.

Shigellosis is a leading global cause of diarrheal disease and travelers' diarrhea now being complicated by the dissemination of antibiotic resistance, necessitating the development of alternative antibacterials such as therapeutic bacteriophages (phages). Phages with lytic activity against Shigella strains were isolated from sewage. The genomes of 32 phages were sequenced, and based on genomic comparisons belong to seven taxonomic genera: Teetrevirus, Teseptimavirus, Kayfunavirus, Tequatrovirus, Mooglevirus, Mosigvirus and Hanrivervirus. Phage host ranges were determined with a diverse panel of 95 clinical isolates of Shigella from Southeast Asia and other geographic regions, representing different species and serotypes. Three-phage mixtures were designed, with one possessing lytic activity against 89% of the strain panel. This cocktail exhibited lytic activity against 100% of S. sonnei isolates, 97.2% of S. flexneri (multiple serotypes) and 100% of S. dysenteriae serotypes 1 and 2. Another 3-phage cocktail composed of two myophages and one podophage showed both a broad host range and the ability to completely sterilize liquid culture of a model virulent strain S. flexneri 2457T. In a Galleria mellonella model of lethal infection with S. flexneri 2457T, this 3-phage cocktail provided a significant increase in survival.

Beneath the surface: Amino acid variation underlying two decades of dengue virus antigenic dynamics in Bangkok, Thailand.

Neutralizing antibodies are important correlates of protection against dengue. Yet, determinants of variation in neutralization across strains within the four dengue virus serotypes (DENV1-4) is imperfectly understood. Studies focus on structural DENV proteins, especially the envelope (E), the primary target of anti-DENV antibodies. Although changes in immune recognition (antigenicity) are often attributed to variation in epitope residues, viral processes influencing conformation and epitope accessibility also affect neutralizability, suggesting possible modulating roles of nonstructural proteins. We estimated effects of residue changes in all 10 DENV proteins on antigenic distances between 348 DENV collected from individuals living in Bangkok, Thailand (1994-2014). Antigenic distances were derived from response of each virus to a panel of twenty non-human primate antisera. Across 100 estimations, excluding 10% of virus pairs each time, 77 of 295 positions with residue variability in E consistently conferred antigenic effects; 52 were within ±3 sites of known binding sites of neutralizing human monoclonal antibodies, exceeding expectations from random assignments of effects to sites (p = 0.037). Effects were also identified for 16 sites on the stem/anchor of E which were only recently shown to become exposed under physiological conditions. For all proteins, except nonstructural protein 2A (NS2A), root-mean-squared-error (RMSE) in predicting distances between pairs held out in each estimation did not outperform sequences of equal length derived from all proteins or E, suggesting that antigenic signals present were likely through linkage with E. Adjusted for E, we identified 62/219 sites embedding the excess signals in NS2A. Concatenating these sites to E additionally explained 3.4% to 4.0% of observed variance in antigenic distances compared to E alone (50.5% to 50.8%); RMSE outperformed concatenating E with sites from any protein of the virus (ΔRMSE, 95%IQR: 0.01, 0.05). Our results support examining antigenic determinants beyond the DENV surface.

Identification and Characterization of vB_PreP_EPr2, a Lytic Bacteriophage of Pan-Drug Resistant Providencia rettgeri.

Providencia rettgeri is an emerging opportunistic Gram-negative pathogen with reports of increasing antibiotic resistance. Pan-drug resistant (PDR) P. rettgeri infections are a growing concern, demonstrating a need for the development of alternative treatment options which is fueling a renewed interest in bacteriophage (phage) therapy. Here, we identify and characterize phage vB_PreP_EPr2 (EPr2) with lytic activity against PDR P. rettgeri MRSN 845308, a clinical isolate that carries multiple antibiotic resistance genes. EPr2 was isolated from an environmental water sample and belongs to the family Autographiviridae, subfamily Studiervirinae and genus Kayfunavirus, with a genome size of 41,261 base pairs. Additional phenotypic characterization showed an optimal MOI of 1 and a burst size of 12.3 ± 3.4 PFU per bacterium. EPr2 was determined to have a narrow host range against a panel of clinical P. rettgeri strains. Despite this fact, EPr2 is a promising lytic phage with potential for use as an alternative therapeutic for treatment of PDR P. rettgeri infections.

Antibody persistence and immune memory response following primary vaccination and boosting with live attenuated SA 14-14-2 Japanese encephalitis vaccine (CD-JEV) in Bangladesh: A phase 4 open-label clinical trial.

INTRODUCTION: Japanese encephalitis (JE) virus is one of the leading causes of viral encephalitis across temperate and tropical zones of Asia. The live attenuated SA 14-14-2 JE vaccine (CD-JEV) is one of three vaccines prequalified by the World Health Organization (WHO) to prevent JE. WHO currently recommends a single CD-JEV dose for infants in endemic settings. However, in the absence of long-term immunogenicity data, WHO has indicated a need for long-term immunogenicity studies to inform optimal dosing schedules and determine the need for booster doses. METHODS: This Phase 4, open-label clinical study measured neutralizing antibody (NAb) titers in Bangladeshi children three and four years after primary CD-JEV vaccination and 7 and 28 days after a booster CD-JEV vaccination given four years after primary vaccination. The study also assessed the tolerability and safety of the booster dose. A NAb titer of ≥1:10 was considered seroprotective. RESULTS: Of 560 children vaccinated between 10 and 12 months of age with CD-JEV three years earlier and enrolled in this study from 30 July 2015 through 03 January 2016, 52 (9.3%; 95% CI: 7.2-12.0) had a seroprotective titer at enrollment. One year later, of 533 children, 66 (12.4%; 95% CI: 9.9-15.5) had a seroprotective titer before receiving a booster dose. Of 524 children who received a booster CD-JEV dose, 479 (91.4%; 95% CI: 88.7-93.5) and 514 (98.1%; 95% CI: 96.5-99.0) were seroprotected 7 and 28 days later, respectively. The geometric mean titer (GMT) was 6 (95% CI: 6-6) at baseline, 105 (95% CI: 93-119) 7 days post-booster, and 167 (95% CI: 152-183) 28 days post-booster. No vaccine-associated neurologic adverse events or other serious adverse events were noted following the booster dose. CONCLUSIONS: Although most children did not have measurable antibody titers three and four years after a single primary CD-JEV dose, more than 90% of seronegative children had a strong anamnestic response within one week of a booster dose. This suggests that these children were immune despite the absence of measurable NAb prior to their booster.ClinicalTrials.gov Identifier: NCT02514746.

Independent Evaluation of Two Prototype Immunochromatographic Tests for Dengue Fever Developed by InBios.

INTRODUCTION: Dengue fever, caused by any of the four dengue viruses (DENV1-4), is endemic in more than 100 countries around the world. Each year, up to 400 million people get infected with dengue virus. It is one of the most important arthropod-borne viral diseases. Dengue's global presence poses a medical threat to deploying military personnel and their dependents. An accurate diagnosis followed by attentive supportive care can improve outcomes in patients with severe dengue disease. Dengue diagnostic tests based on PCR and ELISA platforms have been developed and cleared by the U.S. FDA. However, these diagnostic assays are laborious and usually require highly trained personnel and specialized equipment, which presents a significant challenge when conducting operations in austere and resource-constrained areas. InBios International, Inc. (Seattle, WA) has developed two rapid and instrument-free immunochromatographic test prototype devices (multiplex and traditional formats) for dengue diagnosis. MATERIALS AND METHODS: To determine the performance of the InBios immunochromatographic tests, 183 clinical samples were tested on both prototype devices. Both assays were performed without any instruments and the results were read in 20 minutes. RESULTS: The traditional format had better overall performance (sensitivity: 97.4%; specificity: 90%) than the multiplex format (sensitivity: 86.9%; specificity: 63.3%). The traditional format was superior in serotype-specific detection with 100% overall sensitivity for DENV1, DENV3, and DENV4 and 93.3% sensitivity for DENV2 compared to the multiplex format (91.7%, 78.3%, 83.3%, and 96.3% for DENV1, 2, 3, and 4, respectively). The traditional format was easier to read than the multiplex format. The multiplex format was simpler and faster to set up than the traditional format. CONCLUSIONS: The InBios traditional format had a better overall performance and readability profile than the multiplex format, while the multiplex format was easier to set up. Both formats were highly sensitive and specific, were easy to perform, and did not require sophisticated equipment. They are ideal for use in resource-limited settings where dengue is endemic. Based on our overall assessment, the traditional format should be considered for further development and used in the upcoming multicenter clinical trial toward FDA clearance.

Evaluation of the extended efficacy of the Dengvaxia vaccine against symptomatic and subclinical dengue infection.

More than half of the world's population lives in areas at risk for dengue virus infection. A vaccine will be pivotal to controlling spread, however, the only licensed vaccine, Dengvaxia, has been shown to increase the risk of severe disease in a subset of individuals. Vaccine efforts are hampered by a poor understanding of antibody responses, including those generated by vaccines, and whether antibody titers can be used as a marker of protection from infection or disease. Here we present the results of an ancillary study to a phase III vaccine study (n = 611). All participants received three doses of either Dengvaxia or placebo and were followed for 6 years. We performed neutralization tests on annual samples and during confirmed dengue episodes (n = 16,508 total measurements). We use mathematical models to reconstruct long-term antibody responses to vaccination and natural infection, and to identify subclinical infections. There were 87 symptomatic infections reported, and we estimated that there were a further 351 subclinical infections. Cumulative vaccine efficacy was positive for both subclinical and symptomatic infection, although the protective effect of the vaccine was concentrated in the first 3 years following vaccination. Among individuals with the same antibody titer, we found no difference between the risk of subsequent infection or disease between placebo and vaccine recipients, suggesting that antibody titers are a good predictor of both protection and disease risk.

Genome Sequences of 17 Diverse Pseudomonas aeruginosa Phages.

Here, we describe genome sequences of 17 Pseudomonas aeruginosa phages, including therapeutic candidates. They belong to the families Myoviridae, Podoviridae, and Siphoviridae and six different genera. The genomes ranged in size from 42,788 to 88,805 bp, with G+C contents of 52.5% to 64.3% and numbers of coding sequences from 58 to 179.

Application of One-Step Reverse Transcription Droplet Digital PCR for Dengue Virus Detection and Quantification in Clinical Specimens.

Detection and quantification of viruses in laboratory and clinical samples are standard assays in dengue virus (DENV) studies. The quantitative reverse transcription polymerase chain reaction (qRT-PCR) is considered to be the standard for DENV detection and quantification due to its high sensitivity. However, qRT-PCR offers only quantification relative to a standard curve and consists of several "in-house" components resulting in interlaboratory variations. We developed and optimized a protocol for applying one-step RT-droplet digital PCR (RT-ddPCR) for DENV detection and quantification. The lower limit of detection (LLOD95) and the lower limit of quantification (LLOQ) for RT-ddPCR were estimated to be 1.851 log10-copies/reaction and 2.337 log10-copies/reaction, respectively. The sensitivity of RT-ddPCR was found to be superior to qRT-PCR (94.87% vs. 90.38%, p = 0.039) while no false positives were detected. Quantification of DENV in clinical samples was independently performed in three laboratories showing interlaboratory variations with biases <0.5 log10-copies/mL. The RT-ddPCR protocol presented here could help harmonize DENV quantification results and improve findings in the field such as identifying a DENV titer threshold correlating with disease severity.

Effect of low-passage number on dengue consensus genomes and intra-host variant frequencies.

Intra-host single nucleotide variants (iSNVs) have been increasingly used in genomic epidemiology to increase phylogenetic resolution and reconstruct fine-scale outbreak dynamics. These analyses are preferably done on sequence data from direct clinical samples, but in many cases due to low viral loads, there might not be enough genetic material for deep sequencing and iSNV determination. Isolation of the virus from clinical samples with low-passage number increases viral load, but few studies have investigated how dengue virus (DENV) culture isolation from a clinical sample impacts the consensus sequence and the intra-host virus population frequencies. In this study, we investigate consensus and iSNV frequency differences between DENV sequenced directly from clinical samples and their corresponding low-passage isolates. Twenty five DENV1 and DENV2 positive sera and their corresponding viral isolates (T. splendens inoculation and C6/36 passage) were obtained from a prospective cohort study in the Philippines. These were sequenced on MiSeq with minimum nucleotide depth of coverage of 500×, and iSNVs were detected using LoFreq. For both DENV1 and DENV2, we found a maximum of one consensus nucleotide difference between clinical sample and isolate. Interestingly, we found that iSNVs with frequencies ≥5 % were often preserved between the samples, and that the number of iSNV positions, and sample diversity, at this frequency cutoff did not differ significantly between the sample pairs (clinical sample and isolate) in either DENV1 or DENV2 data. Our results show that low-passage DENV isolate consensus genomes are largely representative of their direct sample parental viruses, and that low-passage isolates often mirror high frequency within-host variants from direct samples.

Temporally integrated single cell RNA sequencing analysis of PBMC from experimental and natural primary human DENV-1 infections.

Dengue human infection studies present an opportunity to address many longstanding questions in the field of flavivirus biology. However, limited data are available on how the immunological and transcriptional response elicited by an attenuated challenge virus compares to that associated with a wild-type DENV infection. To determine the kinetic transcriptional signature associated with experimental primary DENV-1 infection and to assess how closely this profile correlates with the transcriptional signature accompanying natural primary DENV-1 infection, we utilized scRNAseq to analyze PBMC from individuals enrolled in a DENV-1 human challenge study and from individuals experiencing a natural primary DENV-1 infection. While both experimental and natural primary DENV-1 infection resulted in overlapping patterns of inflammatory gene upregulation, natural primary DENV-1 infection was accompanied with a more pronounced suppression in gene products associated with protein translation and mitochondrial function, principally in monocytes. This suggests that the immune response elicited by experimental and natural primary DENV infection are similar, but that natural primary DENV-1 infection has a more pronounced impact on basic cellular processes to induce a multi-layered anti-viral state.

Influenza-Associated Medical Visits Prevented by Influenza Vaccination in Young Children in Thailand, 2012-2014.

Despite recommendations, few children aged 6-35 months in Thailand receive seasonal influenza vaccination. Using previously estimated incidence and vaccine effectiveness data from the period 2012-2014, we estimate that up to 121 000 medical visits could be prevented each year with 50% coverage and expanded recommendations to children aged <5 years.

Incidence of influenza during pregnancy and association with pregnancy and perinatal outcomes in three middle-income countries: a multisite prospective longitudinal cohort study.

BACKGROUND: Influenza vaccination during pregnancy prevents influenza among women and their infants but remains underused among pregnant women. We aimed to quantify the risk of antenatal influenza and examine its association with perinatal outcomes. METHODS: We did a prospective cohort study in pregnant women in India, Peru, and Thailand. Before the 2017 and 2018 influenza seasons, we enrolled pregnant women aged 18 years or older with expected delivery dates 8 weeks or more after the season started. We contacted women twice weekly until the end of pregnancy to identify illnesses with symptoms of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing and collected mid-turbinate nasal swabs from symptomatic women for influenza real-time RT-PCR testing. We assessed the association of antenatal influenza with preterm birth, late pregnancy loss (≥13 weeks gestation), small for gestational age (SGA), and birthweight of term singleton infants using Cox proportional hazards models or generalised linear models to adjust for potential confounders. FINDINGS: Between March 13, 2017, and Aug 3, 2018, we enrolled 11 277 women with a median age of 26 years (IQR 23-31) and gestational age of 19 weeks (14-24). 1474 (13%) received influenza vaccines. 310 participants (3%) had influenza (270 [87%] influenza A and 40 [13%] influenza B). Influenza incidences weighted by the population of women of childbearing age in each study country were 88·7 per 10 000 pregnant woman-months (95% CI 68·6 to 114·8) during the 2017 season and 69·6 per 10 000 pregnant woman-months (53·8 to 90·2) during the 2018 season. Antenatal influenza was not associated with preterm birth (adjusted hazard ratio [aHR] 1·4, 95% CI 0·9 to 2·0; p=0·096) or having an SGA infant (adjusted relative risk 1·0, 95% CI 0·8 to 1·3, p=0·97), but was associated with late pregnancy loss (aHR 10·7, 95% CI 4·3 to 27·0; p<0·0001) and reduction in mean birthweight of term, singleton infants (-55·3 g, 95% CI -109·3 to -1·4; p=0·0445). INTERPRETATION: Women had a 0·7-0·9% risk of influenza per month of pregnancy during the influenza season, and antenatal influenza was associated with increased risk for some adverse pregnancy outcomes. These findings support the added value of antenatal influenza vaccination to improve perinatal outcomes. FUNDING: US Centers for Disease Control and Prevention. TRANSLATIONS: For the Thai, Hindi, Marathi and Spanish translations of the abstract see Supplementary Materials section.

A multi-country field validation of the FluChip-8G Insight Assay.

INTRODUCTION: It is critical to rapidly detect novel and non-seasonal influenza strains. Currently available assays have limited sensitivity in detecting novel influenza subtypes. We performed a multi-country field validation of the FluChip-8G Insight, an assay able to detect and characterize influenza A/B viruses and non-seasonal influenza viruses. MATERIALS AND METHODS: We evaluated the performance of the FluChip-8G Insight on nasal and throat swab clinical samples from Thailand, Philippines and Nepal. Influenza PCR positive and negative samples tested using the US CDC Human Influenza Dx Panel reference standard were selected for testing using the FluChip-8G Influenza Insight. RESULTS: A total of 909 specimens were included in the analysis. The overall sensitivity and specificity of the FluChip-8G Insight to detect combined influenza A+B was 86 % and 100%, respectively. PPV and NPV were estimated at 100 % (95 % CI 99-100) and 73 % (95 % CI 68-78), respectively. Sensitivity across all influenza subtypes was 100% for specimens with <20 and 20-25 Ct values, respectively, but as Ct values increased, sensitivity across all influenza subtypes decreased significantly (p < 0.001) for specimens with Ct values ≥32. CONCLUSION: The FluChip-8G Insight showed good precision and reproducibility among all 3 sites with robust identification of both influenza A and B targets with Ct values <32 and in the absence of co-infection. Positioning this platform in countries considered as hotspots for the emergence of novel/zoonotic influenza strains can increase the lead time in detecting and containing novel influenza strains with pandemic potential.

Immunogenicity and safety of concurrent or sequential administration of live, attenuated SA 14-14-2 Japanese encephalitis vaccine (CD-JEV) and measles-mumps-rubella vaccine in infants 9-12 months of age in the Philippines: A non-inferiority Phase 4 randomized clinical trial.

INTRODUCTION: Japanese encephalitis (JE) virus is the leading cause of viral encephalitis across temperate and tropical zones of Asia. The live attenuated SA 14-14-2 JE vaccine (CD-JEV) is one of three vaccines prequalified by the World Health Organization (WHO) to prevent JE. When incorporating a new vaccine into a country's Expanded Program on Immunization (EPI), it is important to show that the new vaccine can be administered concurrently with other routine pediatric vaccines without impairing the immune responses or changing the safety profiles of the co-administered vaccines. This Phase 4 open-label study evaluated the safety and immunogenicity of measles-mumps-rubella (MMR) vaccine co-administered with CD-JEV. METHODS: The study randomized 628 healthy Filipino children aged between 9 and 10 months to receive MMR and CD-JEV concurrently or separately. MMR immunogenicity was measured 56 days after MMR vaccination using a measles plaque reduction neutralization test (PRNT), anti-mumps immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), and anti-rubella IgG ELISA, respectively. Neutralizing antibody against JE virus was measured 28 days after CD-JEV vaccination using PRNT. Safety was assessed through solicitation of immediate reactions, adverse events (AEs) within 14 days of vaccination, unsolicited AEs occurring within 28 days, and serious adverse events (SAEs) during participation in the study. RESULTS/CONCLUSIONS: During the study, no post-vaccinal encephalitis cases or related SAEs were reported in either group. Concurrent immunization with CD-JEV and MMR vaccines was not associated with any unusual safety signals when compared with sequential immunization. No significant differences between the regimens were seen in seropositivity or serology titer/concentration results for any of the antigens. Co-administration of CD-JEV and MMR was non-inferior to single administration of either vaccine.

Development of an adjuvanted nanoparticle vaccine against influenza virus, an in vitro study.

Influenza is an infectious respiratory illness caused by influenza viruses. Despite yearly updates, the efficacy of influenza vaccines is significantly curtailed by the virus antigenic drift and antigenic shift. These constant changes to the influenza virus make-up also challenge the development of a universal flu vaccine, which requires conserved antigenic regions shared by influenza viruses of different subtypes. We propose that it is possible to bypass these challenges by the development of an influenza vaccine based on conserved proteins delivered in an adjuvanted nanoparticle system. In this study, we generated influenza nanoparticle constructs using trimethyl chitosan nanoparticles (TMC nPs) as the carrier of recombinant influenza hemagglutinin subunit 2 (HA2) and nucleoprotein (NP). The purified HA2 and NP recombinant proteins were encapsulated into TMC nPs to form HA2-TMC nPs and NP-TMC nPs, respectively. Primary human intranasal epithelium cells (HNEpCs) were used as an in vitro model to measure immunity responses. HA2-TMC nPs, NP-TMC nPs, and HA2-NP-TMC nPs (influenza nanoparticle constructs) showed no toxicity in HNEpCs. The loading efficiency of HA2 and NP into the TMC nPs was 97.9% and 98.5%, respectively. HA2-TMC nPs and NP-TMC nPs more efficiently delivered HA2 and NP proteins to HNEpCs than soluble HA2 and NP proteins alone. The induction of various cytokines and chemokines was more evident in influenza nanoparticle construct-treated HNEpCs than in soluble protein-treated HNEpCs. In addition, soluble factors secreted by influenza nanoparticle construct-treated HNEpCs significantly induced MoDCs maturation markers (CD80, CD83, CD86 and HLA-DR), as compared to soluble factors secreted by protein-treated HNEpCs. HNEpCs treated with the influenza nanoparticle constructs significantly reduced influenza virus replication in an in vitro challenge assay. The results indicate that TMC nPs can be used as influenza vaccine adjuvants and carriers capable of delivering HA2 and NP proteins to HNEpCs.