Increase Vaccine Efficacy Research Articles

In silico selection of functionally important proteins from the mialome of Ornithodoros erraticus ticks and assessment of their protective efficacy as vaccine targets

BackgroundNew candidate protective antigens for tick vaccine development may be identified by selecting and testing antigen candidates that play key biological functions. After blood-feeding, tick midgut overexpresses proteins that play essential functions in tick survival and disease transmission. Herein, Ornithodoros erraticus midgut transcriptomic and proteomic data were examined in order to select functionally significant antigens upregulated after feeding to be tested as vaccine candidate antigens.MethodsTranscripts annotated as chitinases, tetraspanins, ribosomal protein P0 and secreted proteins/peptides were mined from the recently published O. erraticus midgut transcriptome and filtered in a second selection step using criteria based on upregulation after feeding, predicted antigenicity and expression in the midgut proteome. Five theoretical candidate antigens were selected, obtained as recombinant proteins and used to immunise rabbits: one chitinase (CHI), two tetraspanins (TSPs), the ribosomal protein P0 (RPP0) and one secreted protein PK-4 (PK4).ResultsRabbit vaccination with individual recombinant candidates induced strong humoral responses that mainly reduced nymph moulting and female reproduction, providing 30.2% (CHI), 56% (TSPs), 57.5% (RPP0) and 57.8% (PK4) protection to O. erraticus infestations and 19.6% (CHI), 11.1% (TSPs), 0% (RPP0) and 8.1% (PK4) cross-protection to infestations by the African tick Ornithodoros moubata. The joint vaccine efficacy of the candidates was assessed in a second vaccine trial reaching 66.3% protection to O. erraticus and 25.6% cross-protection to O. moubata.ConclusionsThese results (i) indicate that argasid chitinases and RPP0 are promising protective antigens, as has already been demonstrated for ixodid chitinases and RPP0, and could be included in vaccines targeting multiple tick species; (ii) reveal novel protective antigens tetraspanins and secreted protein PK-4, never tested before as protective antigens in ticks; and (iii) demonstrate that multi-antigenic vaccines increased vaccine efficacy compared with individual antigens. Lastly, our data emphasize the value of the tick midgut as a source of protective candidate antigens in argasids for tick control.

Simultaneous Administration of Boesenbergia pandurata Extract and Vaccination to Stimulate Immune Response in Tilapia, Oreochromis niloticus.

The use of adjuvants or immunostimulants is often necessary to increase vaccine efficacy, in this study we evaluated the improvement of the immune response in tilapia treated by either oral and immersion administration with vaccine and Boesenbergia pandurata extract (BPE). The initial concentration of BPE and the cell density of vaccine were 900 mg L-1 and 104 CFU mL-1 for oral administration while 106 CFU mL-1 for immersion, respectively. The extract and vaccine were mixed homogeneously in a ratio of 1:1. Further, the mixture was supplemented to feed at 1 mL g-1 feed. Tilapia with average initial body weight of 15 g were fed containing vaccine and BPE 3 times a day. The other group of fish was immersed with vaccine and BPE for 20 min. After 7th (d7), 14th (d14) and21th (d21) days of treatment, a challenge test was conducted by intramuscularly injection of 0.1 mL of Aeromonas hydrophila and Pseudomonas fluorescens mixture (1:1) at a density of 105 CFU mL-1. Antibody levels, total white blood cell (WBC) and phagocytic activity (PA) were evaluated to determine the immune improvement of the fish. Furthermore, relative percent survival (RPS) and the survival rate (SR) were evaluated at week 2 and 4 after challenge test. Results indicated that the all parameters of tilapia immune system were increased (p<0.05) after 2-4 weeks of both administration methods. Meanwhile, the efficacy of the vaccine has increased by combining BPE treatment using immersion method better than oral method. The RPS of vaccination plus extract by immersion was 83-100% and by oral administration was 83-87%. The present results implied that B. pandurata extract boost the efficacy of the Pseudomonas sp. vaccine by increasing the immune system and diseases resistance in tilapia.

Cricket paralysis virus internal ribosome entry site-derived RNA promotes conventional vaccine efficacy by enhancing a balanced Th1/Th2 response

An ideal adjuvant should increase vaccine efficacy through balanced Th1/Th2 responses and be safe to use. Recombinant protein-based vaccines are usually formulated with aluminum (alum)-based adjuvants to ensure an adequate immune response. However, use of alum triggers a Th2-biased immune induction, and hence is not optimal. Although the adjuvanticity of RNA has been reported, a systematic and overall investigation on its efficacy is lacking. We found that single strand RNA (termed RNA adjuvant) derived from cricket paralysis virus intergenic region internal ribosome entry site induced the expression of various adjuvant-function-related genes, such as type 1 and 2 interferon (IFN) and toll-like receptor (TLR), T cell activation, and leukocyte chemotaxis in human peripheral blood mononuclear cells; furthermore, its innate and IFN transcriptome profile patterns were similar to those of a live-attenuated yellow fever vaccine. This suggests that protein-based vaccines formulated using RNA adjuvant function as live-attenuated vaccines. Application of the RNA adjuvant in mouse enhanced the efficacy of Middle East respiratory syndrome spike protein, a protein-subunit vaccine and human papillomavirus L1 protein, a virus-like particle vaccine, by activating innate immune response through TLR7 and enhancing pAPC chemotaxis, leading to a balanced Th1/Th2 responses. Moreover, the combination of alum and the RNA adjuvant synergistically induced humoral and cellular immune responses and endowed long-term immunity. Therefore, RNA adjuvants have broad applicability and can be used with all conventional vaccines to improve vaccine efficacy qualitatively and quantitively.

A Vaccinomics Approach for the Identification of Tick Protective Antigens for the Control of Ixodes ricinus and Dermacentor reticulatus Infestations in Companion Animals.

Ticks and tick-borne pathogens affect health and welfare of companion animals worldwide, and some human tick-borne diseases are associated with exposure to domestic animals. Vaccines are the most environmentally friendly alternative to acaracides for the control of tick infestations, and to reduce the risk for tick-borne diseases affecting human and animal health. However, vaccines have not been developed or successfully implemented for most vector-borne diseases. The main limitation for the development of effective vaccines is the identification of protective antigens. To address this limitation, in this study we used an experimental approach combining vaccinomics based on transcriptomics and proteomics data with vaccination trials for the identification of tick protective antigens. The study was focused on Ixodes ricinus and Dermacentor reticulatus that infest humans, companion animals and other domestic and wild animals, and transmit disease-causing pathogens. Tick larvae and adult salivary glands were selected for analysis to target tick organs and developmental stages playing a key role during tick life cycle and pathogen infection and transmission. Two I. ricinus (heme lipoprotein and uncharacterized secreted protein) and five D. reticulatus (glypican-like protein, secreted protein involved in homophilic cell adhesion, sulfate/anion exchanger, signal peptidase complex subunit 3, and uncharacterized secreted protein) proteins were identified as the most effective protective antigens based on the criteria of vaccine E > 80%. The putative function of selected protective antigens, which are involved in different biological processes, resulted in vaccines affecting multiple tick developmental stages. These results suggested that the combination of some of these antigens might be considered to increase vaccine efficacy through antigen synergy for the control of tick infestations and potentially affecting pathogen infection and transmission. These antigens were proposed for commercial vaccine development for the control of tick infestations in companion animals, and potentially in other hosts for these tick species.

Mathematical models of transmission dynamics and vaccine strategies in Hong Kong during the 2017–2018 winter influenza season

Two mathematical models described by simple ordinary differential equations are developed to investigate the Hong Kong influenza epidemic during 2017–2018 winter, based on overall epidemic dynamics and different influenza subtypes. The first model, describing the overall epidemic dynamics, provides the starting data for the second model which different influenza subtypes, and whose dynamics is further investigated. Weekly data from December 2017 to May 2018 are obtained from the data base of the Centre of Health Protection in Hong Kong, and used to parametrise the models. With the help of these models, we investigate the impact of different vaccination strategies and determine the corresponding critical vaccination coverage for different vaccine efficacies.The results suggest that at least 72% of Hong Kong population should have been vaccinated during 2017–2018 winter to prevent the seasonal epidemic by herd immunity (while data showed that only a maximum of 11.6% of the population were vaccinated). Our results also show that the critical vaccination coverage decreases with increasing vaccine efficacy, and the increase in one influenza subtype vaccine efficacy may lead to an increase in infections caused by a different subtype.

Robust enhancement of tumor-dictated CD8 T cell trafficking and activation by QS21 adjuvanted vaccine

Abstract Adjuvants enhance immune response to antigens and increase vaccine efficacy. We investigated the relative potency of adjuvants with diverse mechanism of action: a natural killer T cell activating ligand (alpha-galactosylcermide, αGalCer), a toll-like receptor 9 ligand (CpG B), a liposomal nanoparticle (R-DOTAP) and a plant saponin from Quillajira saponaria (QS21). We used OVA TCR transgenic model and also compared systemic vs mucosal routes of delivery for inducing antigen-specific CD8 T cell responses in naïve and syngeneic tumor-bearing mice. Wild type C57Bl/6 mice were vaccinated with OVA admixed with the adjuvants via subcutaneous (SC) or intranasal (IN) route 1d after adoptive transfer of the OT-I cells. Single cell suspensions of tissues 7d post-vaccination were analyzed using flow cytometry for OT-1 cells (CD45.1+Vα2+). Vaccination by either SC or IN route using QS21 adjuvant showed the most potent trafficking and activation of CD8+ T cells to both systemic and at mucosal sites, with the highest response observed in the lungs. Vaccination using the αGalCer by the IN route was relatively more effective than when delivered by the SC route, but the responses with αGalCer were lower compared to that with the QS21 adjuvant. However, vaccination of mice bearing B16F10-OVA resulted in preferential trafficking of OT-I cells to the tumors with much reduced numbers at the other tissues. Once again, these responses were robustly higher with QS21 vaccine delivered by either SC or IN route and the OT-1+ T cells from the tumors exhibited higher levels of functional and proliferating properties based on IFN-γ and Ki67 staining. Our results demonstrate that QS21 is a potent adjuvant for prophylactic as well as therapeutic vaccination applications.

PMU14 COST-BENEFIT ANALYSIS OF VACCINATION AGAINST FOUR PREVENTABLE DISEASES IN OLDER ADULTS IN THE UNITED STATES

This study aimed to understand the value of current and expanded vaccination programs against 4 preventable diseases in older adults in the US, accounting for population aging. Cost-benefit analyses were conducted using an underlying population-based, age-structured economic model. This model used annual census projections for adults aged 50 years and older and separate decision trees for influenza, pertussis, herpes zoster, and pneumococcal disease to calculate cases of disease and direct medical and indirect costs (2017 US$). Age- and disease-specific incidence and costs were assumed constant over time. Benefit-cost ratios (BCRs) and net present values (NPVs) were calculated to compare the current vaccination program vs. no vaccination program. Scenario analyses were conducted over multiple time horizons, discount rates, and vaccine coverage and effectiveness assumptions. Compared with no vaccination program, the model projects that the current adult vaccination program is associated with 64.5 million averted cases of disease, $243.5 billion averted costs of cases, and $172.2 billion in incremental vaccination costs over a 30-year period from a societal perspective. For all 4 diseases combined, the resulting NPV is $71.3 billion (BCR = 1.41). vary by disease, with NPVs ranging from $144.9 million (pertussis) to $47.6 billion (pneumococcal) and BCRs ranging from 1.11 (influenza) to 2.95 (pneumococcal). In a scenario with increased vaccine coverage vs. current vaccine coverage for all 4 diseases, the projected societal NPV is $13.9 billion (BCR = 1.14) over a 30-year period. The projected NPV is $22.4 billion for a scenario of increased efficacy for influenza and tetanus-diphtheria-pertussis (Tdap) vaccines (BCR = 1.22). The results from the cost-benefit analyses highlight the value of the adult vaccination program in the US. Additionally, the study suggests that efforts to further increase vaccination rates and vaccine efficacy in older adults may be warranted and economically justifiable.

Anti-V2 antibody deficiency in individuals infected with HIV-1 in Cameroon

The results of the RV144 vaccine clinical trial showed a correlation between high level of anti-V1V2 antibodies (Abs) and a decreased risk of acquiring HIV-1 infection. This turned the focus of HIV vaccine design to the induction of elevated levels of anti-V2 Abs to increase vaccine efficacy. In plasma samples from HIV-1 infected Cameroonian individuals, we observed broad variations in levels of anti-V2 Abs, and 6 of the 79 plasma samples tested longitudinally displayed substantial deficiency of V2 Abs. Sequence analysis of the V2 region from plasma viruses and multivariate analyses of V2 characteristics showed a significant difference in several features between V2-deficient and V2-reactive plasma Abs. These results suggest that HIV vaccine immunogens containing a shorter V2 region with fewer glycosylation sites and higher electrostatic charges can be beneficial for induction of a higher level of anti-V2 Abs and thus contribute to HIV vaccine efficacy.

Combination of RTS,S and Pfs25-IMX313 Induces a Functional Antibody Response Against Malaria Infection and Transmission in Mice.

The last two decades saw a dramatic reduction in malaria incidence rates, but this decrease has been stalling recently, indicating control measures are starting to fail. An effective vaccine, particularly one with a marked effect on disease transmission, would undoubtedly be an invaluable tool for efforts to control and eliminate malaria. RTS,S/AS01, the most advanced malaria vaccine to date, targets the parasite before it invades the liver and has the potential to prevent malaria disease as well as transmission by preventing blood stage infection and therefore gametocytogenesis. Unfortunately efficacy in a phase III clinical trial was limited and it is widely believed that a malaria vaccine needed to contain multiple antigens from different life-cycle stages to have a realistic chance of success. A recent study in mice has shown that partially efficacious interventions targeting the pre-erythrocytic and the sexual lifecycle stage synergise in eliminating malaria from a population over multiple generations. Hence, the combination of RTS,S/AS01 with a transmission blocking vaccine (TBV) is highly appealing as a pragmatic and powerful way to increase vaccine efficacy. Here we demonstrate that combining Pfs25-IMX313, one of the TBV candidates currently in clinical development, with RTS,S/AS01 readily induces a functional immune response against both antigens in outbred CD1 mice. Formulation of Pfs25-IMX313 in AS01 significantly increased antibody titres when compared to formulation in Alhydrogel, resulting in improved transmission reducing activity in standard membrane feeding assays (SMFA). Upon co-formulation of Pfs25-IMX313 with RTS,S/AS01, the immunogenicity of both vaccines was maintained, and functional assessment of the induced antibody response by SMFA and inhibition of sporozoite invasion assay (ISI) showed no reduction in biological activity against parasites of both lifecycle stages. Should this findings be translatable to human vaccination this could greatly aid efforts to eliminate and eventually eradicate malaria.

Increasing FIM2/3 antigen-content improves efficacy of Bordetella pertussis vaccines in mice in vivo without altering vaccine-induced human reactogenicity biomarkers in vitro

Current acellular-pertussis (aP) vaccines appear inadequate for long-term pertussis control because of short-lived efficacy and the increasing prevalence of pertactin-negative isolates which may negatively impact vaccine efficacy. In this study, we added fimbriae (FIM)2 and FIM3 protein to licensed 2-, 3- or 5-component aP vaccines (Pentavac®, Boostrix®, Adacel®, respectively) to assess whether an aP vaccine with enhanced FIM content demonstrates enhanced efficacy. Vaccine-induced protection was assessed in an intranasal mouse challenge model. In addition, potential reactogenicity was measured by biomarkers in a human whole blood assay (WBA) in vitro and benchmarked the responses against licensed whole cell pertussis (wP) and aP vaccines including Easyfive®, Pentavac® and Pentacel®. The results show that commercial vaccines demonstrated reduced efficacy against pertactin-negative versus pertactin-positive strains. However, addition of higher amounts of FIM2/3 to aP vaccines reduced lung colonization and increased vaccine efficacy against a pertactin-negative strain in a dose-dependent manner. Improvements in efficacy were similar for FIM2 and FIM3-expressing strains. Increasing the amount of FIM2/3 proteins in aP formulations did not alter vaccine-induced biomarkers of potential reactogenicity including prostaglandin E2, cytokines and chemokines in human newborn cord and adult peripheral blood tested in vitro. These results suggest that increasing the quantity of FIM proteins in current pertussis vaccine formulations may further enhance vaccine efficacy against B. pertussis infection without increasing the reactogenicity of the vaccine.

Use of UV Treated Milk Powder to Increase Vaccine Efficacy in the Elderly.

Aging populations experience a decline in adaptive immune system function also known as immunosenesence. Protein nutrition has been shown to stimulate and strengthen the immune system, and such approaches are needed for this growing segment of the population. A controlled, randomized, double blind pilot study was conducted to compare two different protein sources (soy and dairy) as nutritional supplementation to enhance vaccine response. Our objective was to examine the immune stimulating effects of dairy protein subjected to ultraviolet radiation (UV-C) radiation treatment process instead of pasteurization. Participants were 21 healthy individuals over 60 years of age who consumed 6 g of the dairy protein or a comparison, soy isoflavone protein, twice a day for 8 weeks. DTaP vaccine administered at week 4. Non-parametric t-tests revealed a significant increase in Tetanus antibodies in the dairy group compared to the soy group at week 8. These findings suggest additional benefits of UV-C treated unheated dairy protein as a solution to counteract immunosenescence, but warrant further study in elderly and other populations that might benefit from immune system stimulation.

Interactomics and tick vaccine development: new directions for the control of tick-borne diseases

ABSTRACTIntroduction: Ticks are obligate hematophagous arthropod ectoparasites that transmit pathogens responsible for a growing number of tick-borne diseases (TBDs) throughout the world. Vaccines have been shown to be the most efficient, cost-effective, and environmentally friendly approach for the control of ticks and the prevention of TBDs. Although at its infancy, interactomics has shown the possibilities that the knowledge of the interactome offers in understanding tick biology and the molecular mechanisms involved in pathogen infection and transmission. Furthermore, interactomics has provided information for the identification of candidate vaccine protective antigens.Areas covered: In this special report, we review the different approaches used for the study of protein–protein physical and functional interactions, and summarize the application of interactomics to the characterization of tick biology and tick–host–pathogen interactions, and the possibilities that offers to vaccine development for the control of ticks and TBDs.Expert commentary: The combination of interacting proteins in antigen formulations may increase vaccine efficacy. In the near future, the combination of interactomics with other omics approaches such as transcriptomics, proteomics, metabolomics, and regulomics together with intelligent Big Data analytic techniques will improve the high throughput discovery and characterization of vaccine protective antigens for the prevention and control of TBDs.

The comparative studies of Borneo plant extracts to increases vaccine efficacy in tilapia, Oreochromis niloticus

&lt;p align="center"&gt;&lt;strong&gt;ABSTRACT &lt;/strong&gt;&lt;/p&gt;&lt;p align="center"&gt;&lt;strong&gt; &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;This study was investigated the adjuvant effect of &lt;em&gt;Boesenbergia pandurata&lt;/em&gt; (BP), &lt;em&gt;Zingiber zerumbet&lt;/em&gt; (ZZ), &lt;em&gt;Solanum ferox&lt;/em&gt;&lt;strong&gt; &lt;/strong&gt;(SF) on protection of tilapia with injection &lt;em&gt;Pseudomonas&lt;/em&gt; sp. (Pseumulvacc) vaccination. The extract concentrations of BP (600 mg/L), ZZ (200 mg/L), and SF (900 mg/L) were combined with the vaccine, ratio between vaccine and extract was 1:1. Tilapia fish (weight 15 g) were intraperitoneally injected with vaccine mix the extract and challenged at days 7 (d7), 14 (d14), and 21 (d21) post vaccination through intramuscular injection with &lt;em&gt;Aeromonas hydrophila&lt;/em&gt; and &lt;em&gt;Pseudomonas fluorescens &lt;/em&gt;(10&lt;sup&gt;5&lt;/sup&gt; CFU/mL each pathogen bacteria). The results shown that the fish with BP+V were found in fin rot at d14 days challenge. The same symptoms was found in ZZ+V at d14 challenge as much 11.11% and 42.86%. while, in the vaccine groups (V), after the challenge, tilapia were found fin rot and darkness color until the last experiment. The BP+V and SF+ZZ+V groups shown reducing the number of bacteria in the fish body after challenge test on d7, d14, and d 21. The efficacy of Pseumulvacc vaccine has increased after its administration with BP (BP+V) on day 7 and day 14 after challenge (90%) and 100% at the time of challenge test d21. The conclusion is &lt;em&gt;B. pandurata&lt;/em&gt; extract might be a promising adjuvant candidate for fish vaccination, and &lt;em&gt;B. pandurata&lt;/em&gt; extract is the best plants as an adjuvant that mixed with the vaccine to against &lt;em&gt;A. hydrophila&lt;/em&gt; and &lt;em&gt;P. fluorescens&lt;/em&gt; infection.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;Keywords: Adjuvant, plant extract, vaccine, fish pathogen bacteria&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p align="center"&gt;&lt;strong&gt;ABSTRAK&lt;/strong&gt;&lt;/p&gt;&lt;p align="center"&gt;&lt;strong&gt; &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Penelitian ini bertujuan untuk mengevaluasi efek adjuvan dari ekstrak tanaman temu kunci (&lt;em&gt;Boesenbergia pandurata&lt;/em&gt;/BP), lempuyang (&lt;em&gt;Zingiber zerumbet&lt;/em&gt;/ZZ), dan terung asam (&lt;em&gt;Solanum ferox&lt;/em&gt;/SF) pada ikan nila yang diberikan bersama dengan vaksin bakteri &lt;em&gt;Pseudomonas&lt;/em&gt; sp. (Pseumulvacc) melalui injeksi. Dosis yang digunakan yaitu ekstrak BP 600 mg/L, ZZ 200 mg/L, dan SF 900 mg/L, dengan rasio antara vaksin dan ekstrak adalah 1:1. Pengujian diawali dengan menginjeksi ikan nila (bobot tubuh 15 g) melalui intraperitoneal dengan campuran vaksin dan ekstrak tanaman, dilanjutkan dengan uji tantang pada hari 7 (d7), 14 (d14) dan 21 (d21) pascavaksinasi dengan bakteri gabungan &lt;em&gt;Aeromonas hydrophila&lt;/em&gt; dan &lt;em&gt;Pseudomonas fluorescens&lt;/em&gt; (kepadatan bakteri masing-masing 10&lt;sup&gt;5&lt;/sup&gt; CFU/mL) melalui intramuskular. Hasil pengujian menunjukkan bahwa ikan yang diberi vaksin dengan penambahan ekstrak BP (BP+V) masih ditemukan mengalami sirip gripis pada waktu uji tantang hari ke 14, gejala serupa juga ditemukan pada pemberian vaksin yang dicampur dengan ZZ (ZZ+V) pada waktu uji tantang d14, sebesar 11.11 % dan 42.86%. Sedangkan ikan yang diberi vaksin tanpa campuran ekstrak (V) masih ditemukan ikan mengalami sirip gripis dan warna menghitam pada waktu uji tantang d14. Pada perlakuan BP+V dan SF+ZZ+V mampu mengurangi jumlah bakteri di dalam tubuh ikan nila pasca uji tantang d7, d14 dan d21, dan jumlahnya lebih rendah dibandingkan dengan perlakuan lainnya. Efikasi vaksin Pseumulvacc mengalami peningkatan pada BP+V pada hari 7 dan hari 14 pasca ujitantang mencapai 90%, dan 100% pada waktu uji tantang d21. Semakin lama waktu uji tantang (d21), berdampak pada tingkat perlindungan vaksin plus ekstrak yang makin tinggi dibandingkan dengan waktu uji tantang pada hari d7 dan d14. Ekstrak &lt;em&gt;B. pandurata&lt;/em&gt; adalah tanaman terbaik sebagai adjuvan yang penggunaannya dicampur dengan vaksin untuk penanggulangan infeksi bakteri &lt;em&gt;A.hydrophila&lt;/em&gt; dan &lt;em&gt;P. fluorescens&lt;/em&gt;.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;Kata kunci: Adjuvan, ekstrak tanaman, vaksin, patogen pada ikan&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Pattern recognition receptor agonists enhance protection elicited by a single, low dose protein vaccine in an immunization route-specific manner

Abstract Despite advances to increase vaccine efficacy, influenza A virus (IAV) remains a significant health risk. Current vaccines against IAV rely on the generation of strain specific antibodies that fail to provide protection against heterosubtypic IAV. Vaccination may be improved through the use of vaccine adjuvants to amplify antigen presenting cell (APC) activation and enhance T and B cell priming. Combined adjuvants that trigger multiple pattern recognition receptors (PRR) are a promising strategy to better mimic live infection. In this study, the efficacy of combining CpG and MPLA, which activate TLR9 and TLR4 respectively, as vaccine adjuvants was examined. It was observed that single, low dose hemagglutinin (HA) protein vaccines containing combination CpG and MPLA delivered intramuscularly (i.m.) or intranasally (i.n.) elicit superior protection against lethal challenge compared to vaccines containing single agonists, as indicated by lower mortality and significantly lower morbidity. Early systemic cytokine responses are being investigated to elucidate the mechanism behind this improved vaccine efficacy. However, it was observed that i.m. administration of combination agonist vaccines induced higher IgG2c antibody responses compared to single agonist vaccines, while minimal levels of antibodies were observed in mice vaccinated i.n. In addition, T cell analysis following lethal infection indicated that i.n. vaccination induces distinct activation profiles compared to i.m. Taken together a comparison of the antibody and T cell profiles of mice vaccinated i.m. and i.n with combined TLR9 and TLR4 agonists suggests that route of vaccination can dictate immune response and may modify effective correlates of protection.

Blocking interleukin-4 enhances efficacy of vaccines for treatment of opioid abuse and prevention of opioid overdose

Vaccines offer an option to treat heroin and prescription opioid abuse and prevent fatal overdoses. Opioid vaccines elicit antibodies that block opioid distribution to the brain and reduce opioid-induced behavioral effects and toxicity. The major limitation to the translation of addiction vaccines is that efficacy is observed only in subjects achieving optimal drug-specific serum antibody levels. This study tested whether efficacy of a vaccine against oxycodone is increased by immunomodulators targeting key cytokine signaling pathways involved in B and T cell lymphocyte activation. Blockage of IL-4 signaling increased vaccine efficacy in blocking oxycodone distribution to the brain and protection against opioid-induced behavior and toxicity in mice. This strategy generalized to a peptide-protein conjugate immunogen, and a tetanus-diphtheria-pertussis vaccine. These data demonstrate that cytokine-based immunomodulators increase efficacy of vaccines against small molecules, peptides and proteins, and identify IL-4 as a pharmacological target for improving efficacy of next-generation vaccines.

Unsaturated Squalene Content in Emulsion Vaccine Adjuvants Plays a Crucial Role in ROS-Mediated Antigen Uptake and Cellular Immunity.

Emulsion-based adjuvants have been demonstrated to be an effective tool in increasing vaccine efficacy. Here, we aimed to launch a mechanistic study on how emulsion adjuvants interact with immune cells and to elucidate the roles of the core oil in vaccine immunogenicity. Our results showed that treatment of dendritic cells (DCs) and splenocytes with a squalene-based emulsion (referred as SqE) induced reactive oxidative species (ROS) production and resulted in an increase in apoptotic and necrotic cells in a concentration- and time-dependent manner. Furthermore, DCs cocultured with cellular debris of SqE-pretreated splenocytes resulted in a higher level of ovalbumin (OVA) antigen uptake by DCs than those cocultured with untreated splenocytes. Interestingly, the potency was rather attenuated when splenocytes were pretreated with N-acetyl-cysteine, an antioxidant. Notably, SqE possesses a high impact on eliciting ROS-mediated antigen uptake compared with a squalane-based emulsion (SqA). Concordantly, immunogenicity studies have shown that SqE is better able than SqA to activate antigen-presenting cells, and to enhance antigen-specific T-cell immunity. Taken together, our results show that unsaturated squalene oil cored within emulsions plays a crucial role in ROS-mediated antigen uptake and cellular immunity, providing a basis for the design and development of vaccine adjuvant.

Coadministration of the Campylobacter jejuni N-Glycan-Based Vaccine with Probiotics Improves Vaccine Performance in Broiler Chickens.

Source attribution studies report that the consumption of contaminated poultry is the primary source for acquiring human campylobacteriosis. Oral administration of an engineered Escherichia coli strain expressing the Campylobacter jejuni N-glycan reduces bacterial colonization in specific-pathogen-free leghorn chickens, but only a fraction of birds respond to vaccination. Optimization of the vaccine for commercial broiler chickens has great potential to prevent the entry of the pathogen into the food chain. Here, we tested the same vaccination approach in broiler chickens and observed similar efficacies in pathogen load reduction, stimulation of the host IgY response, the lack of C. jejuni resistance development, uniformity in microbial gut composition, and the bimodal response to treatment. Gut microbiota analysis of leghorn and broiler vaccine responders identified one member of Clostridiales cluster XIVa, Anaerosporobacter mobilis, that was significantly more abundant in responder birds. In broiler chickens, coadministration of the live vaccine with A. mobilis or Lactobacillus reuteri, a commonly used probiotic, resulted in increased vaccine efficacy, antibody responses, and weight gain. To investigate whether the responder-nonresponder effect was due to the selection of a C. jejuni "supercolonizer mutant" with altered phase-variable genes, we analyzed all poly(G)-containing loci of the input strain compared to nonresponder colony isolates and found no evidence of phase state selection. However, untargeted nuclear magnetic resonance (NMR)-based metabolomics identified a potential biomarker negatively correlated with C. jejuni colonization levels that is possibly linked to increased microbial diversity in this subgroup. The comprehensive methods used to examine the bimodality of the vaccine response provide several opportunities to improve the C. jejuni vaccine and the efficacy of any vaccination strategy.IMPORTANCECampylobacter jejuni is a common cause of human diarrheal disease worldwide and is listed by the World Health Organization as a high-priority pathogen. C. jejuni infection typically occurs through the ingestion of contaminated chicken meat, so many efforts are targeted at reducing C. jejuni levels at the source. We previously developed a vaccine that reduces C. jejuni levels in egg-laying chickens. In this study, we improved vaccine performance in meat birds by supplementing the vaccine with probiotics. In addition, we demonstrated that C. jejuni colonization levels in chickens are negatively correlated with the abundance of clostridia, another group of common gut microbes. We describe new methods for vaccine optimization that will assist in improving the C. jejuni vaccine and other vaccines under development.

Parainfluenza Virus 5 Expressing Wild-Type or Prefusion Respiratory Syncytial Virus (RSV) Fusion Protein Protects Mice and Cotton Rats from RSV Challenge.

Human respiratory syncytial virus (RSV) is the leading cause of pediatric bronchiolitis and hospitalizations. RSV can also cause severe complications in elderly and immunocompromised individuals. There is no licensed vaccine. We previously generated a parainfluenza virus 5 (PIV5)-vectored vaccine candidate expressing the RSV fusion protein (F) that was immunogenic and protective in mice. In this work, our goal was to improve the original vaccine candidate by modifying the PIV5 vector or by modifying the RSV F antigen. We previously demonstrated that insertion of a foreign gene at the PIV5 small hydrophobic (SH)-hemagglutinin-neuraminidase (HN) junction or deletion of PIV5 SH increased vaccine efficacy. Additionally, other groups have demonstrated that antibodies against the prefusion conformation of RSV F have more potent neutralizing activity than antibodies against the postfusion conformation. Therefore, to improve on our previously developed vaccine candidate, we inserted RSV F at the PIV5 SH-HN gene junction or used RSV F to replace PIV5 SH. We also engineered PIV5 to express a prefusion-stabilized F mutant. The candidates were tested in BALB/c mice via the intranasal route and induced both humoral and cell-mediated immunity. They also protected against RSV infection in the mouse lung. When they were administered intranasally or subcutaneously in cotton rats, the candidates were highly immunogenic and reduced RSV loads in both the upper and lower respiratory tracts. PIV5-RSV F was equally protective when administered intranasally or subcutaneously. In all cases, the prefusion F mutant did not induce higher neutralizing antibody titers than wild-type F. These results show that antibodies against both pre- and postfusion F are important for neutralizing RSV and should be considered when designing a vectored RSV vaccine. The findings also that indicate PIV5-RSV F may be administered subcutaneously, which is the preferred route for vaccinating infants, who may develop nasal congestion as a result of intranasal vaccination.IMPORTANCE Despite decades of research, human respiratory syncytial virus (RSV) is still a major health concern for which there is no vaccine. A parainfluenza virus 5-vectored vaccine expressing the native RSV fusion protein (F) has previously been shown to confer robust immunity against RSV infection in mice, cotton rats, and nonhuman primates. To improve our previous vaccine candidate, we developed four new candidates that incorporate modifications to the PIV5 backbone, replace native RSV F with a prefusion-stabilized RSV F mutant, or combine both RSV F and PIV5 backbone modifications. In this work, we characterized the new vaccine candidates and tested their efficacies in both murine and cotton rat models of RSV infection. Most importantly, we found that PIV5-based RSV vaccine candidates were efficacious in preventing lower respiratory tract infection as well as in reducing the nasal viral load when administered via the subcutaneous route.

Dependency of Vaccine Efficacy on Preexposure and Age: A Closer Look at a Tetravalent Dengue Vaccine.

A recombinant, live-attenuated, tetravalent dengue vaccine (CYD-TDV) was licensed for children aged ≥9 years in a few countries, but the dependence of vaccine efficacy on baseline immunity status and age groups has not been fully characterized. Combining the 2 phase 3 trials CYD14 and CYD15, we estimated the vaccine efficacy for each of the 4 serotypes of dengue virus (DENV), as well as all serotypes combined, simultaneously stratified by baseline immunity status and age group, while accounting for uncertainty in the baseline immunity status of subjects. Baseline seropositive subjects showed high efficacy for all serotypes: 70.2% (95% confidence interval [CI], 57.4%-80.1%) for dengue serotype 1 (DENV-1), 67.9% (95% CI, 49.9%-82.0%) for DENV-2, 77.5% (95% CI, 64.3%-90.2%) for DENV-3, 89.9% (95% CI, 79.8%-99.9%) for DENV-4, and 75.4% (95% CI, 68.3%-81.6%) overall. In contrast, baseline seronegative subjects showed moderate efficacy against DENV-4 (51.2% [95% CI, 20.0%-72.8%]) but no significant efficacy against other serotypes. Among seropositive children, the overall efficacy tended to increase with age: 35.9% (95% CI, -7.6% to 69.3%) for children ≤5 years old, 65.6% (95% CI, 40.3%-84.2%) for those 6-8 years old, 73.4% (95% CI, 62.6%-82.1%) for those 9-11 years old, and 80.6% (95% CI, 72.9%-87.3%) for those 12 years or older. The CYD-TDV vaccine was highly efficacious for all dengue serotypes among children aged >5 years who have acquired baseline immunity from previous exposure. Increasing vaccine efficacy with age was not fully explained by increasing prevalence of baseline immunity with age.

Blockade of only TGF-β 1 and 2 is sufficient to enhance the efficacy of vaccine and PD-1 checkpoint blockade immunotherapy

ABSTRACTCheckpoint inhibition has established immunotherapy as a major modality of cancer treatment. However, the success of cancer immunotherapy is still limited as immune regulation of tumor immunity is very complicated and mechanisms involved may also differ among cancer types. Beside checkpoints, other good candidates for immunotherapy are immunosuppressive cytokines. TGF-β is a very potent immunosuppressive cytokine involved in suppression of tumor immunity and also necessary for the function of some regulatory cells. TGF-β has three isoforms, TGF-β 1, 2 and 3. It has been demonstrated in multiple mouse tumor models that inhibition of all three isoforms of TGF-β facilitates natural tumor immunosurveillance and tumor vaccine efficacy. However, individual isoforms of TGF-β are not well studied yet. Here, by using monoclonal antibodies (mAbs) specific for TGF-β isoforms, we asked whether it is necessary to inhibit TGF-β3 to enhance tumor immunity. We found that blockade of TGF-β1 and 2 and of all isoforms provided similar effects on tumor natural immunosurveillance and therapeutic vaccine-induced tumor immunity. The protection was CD8+ T cell-dependent. Blockade of TGF-β increased vaccine-induced Th1-type response measured by IFNγ production or T-bet expression in both tumor draining lymph nodes and tumors, although it did not increase tumor antigen-specific CD8+ T cell numbers. Therefore, protection correlated with qualitative rather than quantitative changes in T cells. Furthermore, when combined with PD-1 blockade, blockade of TGF-β1 and 2 further increased vaccine efficacy. In conclusion, blocking TGF-β1 and 2 is sufficient to enhance tumor immunity, and it can be further enhanced with PD-1 blockade.