Application of "Systems Vaccinology" to Evaluate Inflammation and Reactogenicity of Adjuvanted Preventative Vaccines

Reactive axillary lymph nodes after COVID-19 mRNA vaccination: comparison of mRNA vs. attenuated whole-virus vaccines

OBJECTIVE

To compare the incidence and natural course of reactive axillary lymph nodes (RAL) between mRNA and attenuated whole-virus vaccines using Deauville criteria.

METHODS

In this multi-institutional PET-CT study comprising multiple vaccine types (Pfizer-BioNTech/Comirnaty, Moderna/Spikevax, Sinovac/CoronaVac and Janssen vaccines), we evaluated the incidence and natural course of RAL in a large cohort of oncological patients utilizing a standardized Deauville scaling system (n=522; 293 Female, Deauville 3-5 positive for RAL). Univariate and multivariate analyses were conducted to evaluate the predictive value of clinical parameters (absolute neutrophil count [ANC], platelets, age, sex, tumor type, and vaccine-to-PET interval) for PET positivity.

RESULTS

Pfizer-BioNTech/Comirnaty and Moderna vaccines revealed similar RAL incidences for the first 20 days after the second dose of vaccine administration (44% for the first 10 days for both groups, 26% vs. 20% for 10-20 days, respectively for Moderna and Pfizer). However, Moderna recipients revealed significantly higher incidences of RAL after 20 days compared to Pfizer-BioNTech/Comirnaty, with nodal reactivity spanning up to the 9th week post-vaccination (15% vs. 4%, respectively P  < 0.001). No RAL was observed in patients who received either a single dose of J&J vaccine or two doses of CroronaVac. Younger patients showed increased likelihood of RAL, otherwise, clinical/demographic parameters were not predictive of RAL ( P  = 0.014 for age, P  > 0.05 for additional clinical/demographic parameters).

CONCLUSION

RAL based on strict PET criteria was observed with mRNA but not with attenuated whole-virus vaccines, in line with higher immunogenicity and stronger protection offered by mRNA vaccines.

A Predictive Model of Vaccine Reactogenicity Using Data from an In Vitro Human Innate Immunity Assay System

A primary concern in vaccine development is safety, particularly avoiding an excessive immune reaction in an otherwise healthy individual. An accurate prediction of vaccine reactogenicity using in vitro assays and computational models would facilitate screening and prioritization of novel candidates early in the vaccine development process. Using the modular in vitro immune construct model of human innate immunity, PBMCs from 40 healthy donors were treated with 10 different vaccines of varying reactogenicity profiles and then cell culture supernatants were analyzed via flow cytometry and a multichemokine/cytokine assay. Differential response profiles of innate activity and cell viability were observed in the system. In parallel, an extensive adverse event (AE) dataset for the vaccines was assembled from clinical trial data. A novel reactogenicity scoring framework accounting for the frequency and severity of local and systemic AEs was applied to the clinical data, and a machine learning approach was employed to predict the incidence of clinical AEs from the in vitro assay data. Biomarker analysis suggested that the relative levels of IL-1B, IL-6, IL-10, and CCL4 have higher predictive importance for AE risk. Predictive models were developed for local reactogenicity, systemic reactogenicity, and specific individual AEs. A forward-validation study was performed with a vaccine not used in model development, Trumenba (meningococcal group B vaccine). The clinically observed Trumenba local and systemic reactogenicity fell on the 26th and 93rd percentiles of the ranges predicted by the respective models. Models predicting specific AEs were less accurate. Our study presents a useful framework for the further development of vaccine reactogenicity predictive models.

Identifying Safety Subgroups at Risk: Assessing the Agreement Between Statistical Alerting and Patient Subgroup Risk

INTRODUCTION

Identifying individual characteristics or underlying conditions linked to adverse drug reactions (ADRs) can help optimise the benefit-risk ratio for individuals. A systematic evaluation of statistical methods to identify subgroups potentially at risk using spontaneous ADR report datasets is lacking.

OBJECTIVES

In this study, we aimed to assess concordance between subgroup disproportionality scores and European Medicines Agency Pharmacovigilance Risk Assessment Committee (PRAC) discussions of potential subgroup risk.

METHODS

The subgroup disproportionality method described by Sandberg et al., and variants, were applied to statistically screen for subgroups at potential increased risk of ADRs, using data from the US FDA Adverse Event Reporting System (FAERS) cumulative from 2004 to quarter 2 2021. The reference set used to assess concordance was manually extracted from PRAC minutes from 2015 to 2019. Mentions of subgroups presenting potential differentiated risk and overlapping with the Sandberg method were included.

RESULTS

Twenty-seven PRAC subgroup examples representing 1719 subgroup drug-event combinations (DECs) in FAERS were included. Using the Sandberg methodology, 2 of the 27 could be detected (one for age and one for sex). No subgroup examples for pregnancy and underlying condition were detected. With a methodological variant, 14 of 27 examples could be detected.

CONCLUSIONS

We observed low concordance between subgroup disproportionality scores and PRAC discussions of potential subgroup risk. Subgroup analyses performed better for age and sex, while for covariates not well-captured in FAERS, such as underlying condition and pregnancy, additional data sources should be considered.

MRI/PET multimodal imaging of the innate immune response in skeletal muscle and draining lymph node post vaccination in rats

The goal of this study was to utilize a multimodal magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging approach to assess the local innate immune response in skeletal muscle and draining lymph node following vaccination in rats using two different vaccine platforms (AS01 adjuvanted protein and lipid nanoparticle (LNP) encapsulated Self-Amplifying mRNA (SAM)). MRI and ¹⁸FDG PET imaging were performed temporally at baseline, 4, 24, 48, and 72 hr post Prime and Prime-Boost vaccination in hindlimb with Cytomegalovirus (CMV) gB and pentamer proteins formulated with AS01, LNP encapsulated CMV gB protein-encoding SAM (CMV SAM), AS01 or with LNP carrier controls. Both CMV AS01 and CMV SAM resulted in a rapid MRI and PET signal enhancement in hindlimb muscles and draining popliteal lymph node reflecting innate and possibly adaptive immune response. MRI signal enhancement and total ¹⁸FDG uptake observed in the hindlimb was greater in the CMV SAM vs CMV AS01 group (↑2.3 - 4.3-fold in AUC) and the MRI signal enhancement peak and duration were temporally shifted right in the CMV SAM group following both Prime and Prime-Boost administration. While cytokine profiles were similar among groups, there was good temporal correlation only between IL-6, IL-13, and MRI/PET endpoints. Imaging mass cytometry was performed on lymph node sections at 72 hr post Prime and Prime-Boost vaccination to characterize the innate and adaptive immune cell signatures. Cell proximity analysis indicated that each follicular dendritic cell interacted with more follicular B cells in the CMV AS01 than in the CMV SAM group, supporting the stronger humoral immune response observed in the CMV AS01 group. A strong correlation between lymph node MRI T2 value and nearest-neighbor analysis of follicular dendritic cell and follicular B cells was observed (r=0.808, P<0.01). These data suggest that spatiotemporal imaging data together with AI/ML approaches may help establish whether in vivo imaging biomarkers can predict local and systemic immune responses following vaccination.

Immunogenicity and Reactogenicity in Q Fever Vaccine Development

Coxiella burnetii is an obligate intracellular bacterium which, in humans, causes the disease Q fever. Although Q fever is most often a mild, self-limiting respiratory disease, it can cause a range of severe syndromes including hepatitis, myocarditis, spontaneous abortion, chronic valvular endocarditis, and Q fever fatigue syndrome. This agent is endemic worldwide, except for New Zealand and Antarctica, transmitted via aerosols, persists in the environment for long periods, and is maintained through persistent infections in domestic livestock. Because of this, elimination of this bacterium is extremely challenging and vaccination is considered the best strategy for prevention of infection in humans. Many vaccines against C. burnetii have been developed, however, only a formalin-inactivated, whole cell vaccine derived from virulent C. burnetii is currently licensed for use in humans. Unfortunately, widespread use of this whole cell vaccine is impaired due to the severity of reactogenic responses associated with it. This reactogenicity continues to be a major barrier to access to preventative vaccines against C. burnetii and the pathogenesis of this remains only partially understood. This review provides an overview of past and current research on C. burnetii vaccines, our knowledge of immunogenicity and reactogenicity in C. burnetii vaccines, and future strategies to improve the safety of vaccines against C. burnetii.

Paving the Way Towards Precision Vaccinology: The Paradigm of Myocarditis After Coronavirus Disease 2019 (COVID-19) Vaccination

Systems vaccinology approaches have introduced novel tools for the evaluation of the safety profile of novel vaccine antigens by developing biomarkers of vaccine reactogenicity associated with potential adverse events. The use of such approaches may prove extremely advantageous in the context of a global pandemic where accelerated approval of new vaccine formulations for all ages is essential for the containment of the epidemic. The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had devastating effects on global health, but the emergency authorization of mRNA vaccines significantly reduced SARS-CoV-2-associated morbidity and mortality. Despite their favorable safety profile in adult populations, recent reports have raised concerns about an association of the mRNA-based vaccines with acute myocarditis, predominantly among male adolescents and young adults following the second vaccine dose. Here, we review data on myocarditis epidemiology following SARS-CoV-2 mRNA vaccination and describe potential mechanisms involved that may explain the sex- and age-related differences, focusing on mRNA immune reactivity. The case of vaccine-associated myocarditis highlights the need to incorporate precision vaccinology approaches for the development of safe and effective vaccines for everyone.

Utility of urinary cytokine levels as predictors of the immunogenicity and reactogenicity of AS01-adjuvanted hepatitis B vaccine in healthy adults

Plasma cytokines are useful indicators of the inflammatory response to vaccination, and can serve as potential biomarkers of the systemic reactogenicity and immunogenicity of vaccines. Measurement of cytokines in urine may represent a non-invasive alternative to the blood-based markers. To evaluate whether urinary cytokine levels can help predict vaccine responses to an AS01_B-adjuvanted vaccine, we measured concentrations of 24 cytokines in the urine from 30 hepatitis B virus (HBV)-naïve adults following administration of AS01_B-adjuvanted HBV surface antigen vaccine (NCT01777295). Levels post-dose 2 were compared with the levels measured following a single placebo (saline) injection, which was administered 1 month before the first vaccination in the same participants. Urine was collected at eight timepoints before or up to 1 week following each treatment. Urinary concentrations were normalized to creatinine levels, and paired with previously reported, participant-matched plasma levels, local and systemic reactogenicity scores, and antibody response magnitudes. Of the urine cytokine panel, only few analytes were detectable: IL-8, IL-18 and IL-6 receptor, each showing no clear changes after vaccination as compared to placebo administration, and MCP-1 (CCL2) and IP-10 (CXCL10), which displayed in most participants transient surges post-vaccination. Urine levels did not correlate with the matched plasma levels. Interestingly, urinary IP-10 levels at 1 day post-second vaccination were significantly correlated (P = 0.023) with the concurrent intensity scores of systemic reactogenicity, though not with the local reactogenicity scores or peak antibody responses. No significant correlations were detected for MCP-1. Altogether, most urinary cytokines have limited utility as a proxy for plasma cytokines to help predict the inflammatory response, the immunogenicity or the reactogenicity of AS01_B-adjuvanted vaccine, with the possible exception of IP-10. The utility of urinary IP-10 as a potential complementary biomarker of systemic vaccine reactogenicity needs substantiation in larger studies.

Combating Childhood Infections in LMICs: evaluating the contribution of Big Data Big data, biomarkers and proteomics: informing childhood diarrhoeal disease management in Low- and Middle-Income Countries

Despite efforts to reduce the global burden of childhood diarrhoea, 50% of all cases globally occur in children under five years in Low–Income and Middle- Income Countries (LMICs) and knowledge gaps remain regarding the aetiological diagnosis, introduction of diarrhoeal vaccines, and the role of environmental enteric dysfunction and severe acute malnutrition. Biomarkers may assist in understanding disease processes, from diagnostics, to management of childhood diarrhoea and the sequelae to vaccine development. Proteomics has the potential to assist in the identification of new biomarkers to understand the processes in the development of childhood diarrhoea and to aid in developing new vaccines. Centralised repositories that enable mining of large data sets to better characterise risk factors, the proteome of both the patient and the different diarrhoeal pathogens, and the environment, could inform patient management and vaccine development, providing a systems biological approach to address the burden of childhood diarrhoea in LMICs.

Predictive Markers of Immunogenicity and Efficacy for Human Vaccines

Vaccines represent one of the major advances of modern medicine. Despite the many successes of vaccination, continuous efforts to design new vaccines are needed to fight "old" pandemics, such as tuberculosis and malaria, as well as emerging pathogens, such as Zika virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Vaccination aims at reaching sterilizing immunity, however assessing vaccine efficacy is still challenging and underscores the need for a better understanding of immune protective responses. Identifying reliable predictive markers of immunogenicity can help to select and develop promising vaccine candidates during early preclinical studies and can lead to improved, personalized, vaccination strategies. A systems biology approach is increasingly being adopted to address these major challenges using multiple high-dimensional technologies combined with in silico models. Although the goal is to develop predictive models of vaccine efficacy in humans, applying this approach to animal models empowers basic and translational vaccine research. In this review, we provide an overview of vaccine immune signatures in preclinical models, as well as in target human populations. We also discuss high-throughput technologies used to probe vaccine-induced responses, along with data analysis and computational methodologies applied to the predictive modeling of vaccine efficacy.

Systematic Evaluation of Kinetics and Distribution of Muscle and Lymph Node Activation Measured by 18F-FDG- and 11C-PBR28-PET/CT Imaging, and Whole Blood and Muscle Transcriptomics After Immunization of Healthy Humans With Adjuvanted and Unadjuvanted Vaccines

Systems vaccinology has been applied to detect signatures of human vaccine induced immunity but its ability, together with high definition in vivo clinical imaging is not established to predict vaccine reactogenicity. Within two European Commission funded high impact programs, BIOVACSAFE and ADITEC, we applied high resolution positron emission tomography/computed tomography (PET/CT) scanning using tissue-specific and non-specific radioligands together with transcriptomic analysis of muscle biopsies in a clinical model systematically and prospectively comparing vaccine-induced immune/inflammatory responses. 109 male participants received a single immunization with licensed preparations of either AS04-adjuvanted hepatitis B virus vaccine (AHBVV); MF59C-adjuvanted (ATIV) or unadjuvanted seasonal trivalent influenza vaccine (STIV); or alum-OMV-meningococcal B protein vaccine (4CMenB), followed by a PET/CT scan (n = 54) or an injection site muscle biopsy (n = 45). Characteristic kinetics was observed with a localized intramuscular focus associated with increased tissue glycolysis at the site of immunization detected by ¹⁸F-fluorodeoxyglucose (FDG) PET/CT, peaking after 1–3 days and strongest and most prolonged after 4CMenB, which correlated with clinical experience. Draining lymph node activation peaked between days 3–5 and was most prominent after ATIV. Well defined uptake of the immune cell-binding radioligand ¹¹C-PBR28 was observed in muscle lesions and draining lymph nodes. Kinetics of muscle gene expression module upregulation reflected those seen previously in preclinical models with a very early (~6hrs) upregulation of monocyte-, TLR- and cytokine/chemokine-associated modules after AHBVV, in contrast to a response on day 3 after ATIV, which was bracketed by whole blood responses on day 1 as antigen presenting, inflammatory and innate immune cells trafficked to the site of immunization, and on day 5 associated with activated CD4+ T cells. These observations confirm the use of PET/CT, including potentially tissue-, cell-, or cytokine/chemokine-specific radioligands, is a safe and ethical quantitative technique to compare candidate vaccine formulations and could be safely combined with biopsy to guide efficient collection of samples for integrated whole blood and tissue systems vaccinology in small-scale but intensive human clinical models of immunization and to accelerate clinical development and optimisation of vaccine candidates, adjuvants, and formulations.

Safety biomarkers for development of vaccines and biologics: Report from the safety biomarkers symposium held on November 28-29, 2017, Marcy l'Etoile, France

Vaccines prevent infectious diseases, but vaccination is not without risk and adverse events are reported although they are more commonly reported for biologicals than for vaccines. Vaccines and biologicals must undergo vigorous assessment before and after licensure to minimise safety concerns. Potential safety concerns should be identified as early as possible during the development for vaccines and biologicals to minimize investment risk. State-of-the art tools and methods to identify safety concerns and biomarkers that are predictive of clinical outcomes are indispensable. For vaccines and adjuvant formulations, systems biology approaches, supported by single-cell microfluidics applied to translational studies between preclinical and clinical studies, could improve reactogenicity and safety predictions. Next-generation animal models for clinical assessment of injection-site reactions with greater relevance for target human population and criteria to define the level of acceptability of local reactogenicity at vaccine injection sites in pre-clinical animal species should be assessed. Advanced in silico machine-learning-based analytics, species-specific cell or tissue expression, receptor occupancy and kinetics and cell-based assays for functional activity are needed to improve pre-clinical safety assessment of biologicals. The in vitro MIMIC® system could be used to compliment preclinical and clinical studies for assessing immune-toxicity, immunogenicity, immuno-inflammatory and mode of action of biologicals and vaccines. Sanofi Pasteur brought together leading experts in this field to review the state-of-the-art at a unique 'Safety Biomarkers Symposium' on 28-29 November 2017. Here we summarise the proceedings of this symposium. This unique scientific meeting confirmed the importance for institutions and industrial organizations to collaborate to develop tools and methods needed for predicting reactogenicity and immune-inflammatory reactions to vaccines and biologicals, and to develop more accuracy, reliability safety biomarkers, to inform decisions on the attrition or advancement of vaccines and biologicals.

The combination of artificial intelligence and systems biology for intelligent vaccine design

INTRODUCTION

A new body of evidence depicts the applications of artificial intelligence and systems biology in vaccine design and development. The combination of both approaches shall revolutionize healthcare, accelerating clinical trial processes and reducing the costs and time involved in drug research and development.

AREAS COVERED

This review explores the basics of artificial intelligence and systems biology approaches in the vaccine development pipeline. The topics include a detailed description of epitope prediction tools for designing epitope-based vaccines and agent-based models for immune system response prediction, along with a focus on their potentiality to facilitate clinical trial phases.

EXPERT OPINION

Artificial intelligence and systems biology offer the opportunity to avoid the inefficiencies and failures that arise in the classical vaccine development pipeline. One promising solution is the combination of both methodologies in a multiscale perspective through an accurate pipeline. We are entering an 'in silico era' in which scientific partnerships, including a more and more increasing creation of an 'ecosystem' of collaboration and multidisciplinary approach, are relevant for addressing the long and risky road of vaccine discovery and development. In this context, regulatory guidance should be developed to qualify the in silico trials as evidence for intelligent vaccine development.

Current Challenges in Vaccinology

The development of vaccines, which prime the immune system to respond to future infections, has led to global declines in morbidity and mortality from dreadful infectious communicable diseases. However, many pathogens of public health importance are highly complex and/or rapidly evolving, posing unique challenges to vaccine development. Several of these challenges include an incomplete understanding of how immunity develops, host and pathogen genetic variability, and an increased societal skepticism regarding vaccine safety. In particular, new high-dimensional omics technologies, aided by bioinformatics, are driving new vaccine development (vaccinomics). Informed by recent insights into pathogen biology, host genetic diversity, and immunology, the increasing use of genomic approaches is leading to new models and understanding of host immune system responses that may provide solutions in the rapid development of novel vaccine candidates.

Obesity and Sex Affect the Immune Responses to Tick-Borne Encephalitis Booster Vaccination

Obesity has dramatically increased over the last 30 years and reaches according to World Health Organization dimensions of a global epidemic. The obesity-associated chronic low-level inflammation contributes to severe comorbidities and directly affects many immune cells leading to immune dysfunction and increased susceptibility to infections. Thus, prophylaxis against vaccine-preventable diseases is crucial, yet the responsiveness to several vaccines is unclear under obesity. In order to assess the responsiveness to tick-borne encephalitis (TBE) vaccine, we revaccinated 37 obese individuals and 36 normal-weight controls with a licensed TBE vaccine. Metabolic, hormonal, and immunologic profiles along with vaccine-specific humoral and cellular immune responses were evaluated in sera and peripheral blood mononuclear cells (PBMCs) before, 1 week, 4 weeks, and 6 months after TBE booster. Obese adults had significantly increased metabolic (triglycerides, cholesterol ratios, leptin, insulin) and proinflammatory (C-reactive protein) parameters. They showed stronger initial increase of TBE-specific Ab titers (d7_d28) followed by a significantly faster decline after 6 months, which correlated with high body mass index and leptin and insulin levels. The fold increase of Ab-titer levels was significantly higher in obese compared to control males and linked to reduced testosterone levels. Obesity also affected cellular responses: PBMCs of the obese vaccinees had elevated interleukin 2 and interferon γ levels upon antigen stimulation, indicating a leptin-dependent proinflammatory T_H1 polarization. The expansion of total and naive B cells in obese might explain the initial increase of Ab titers, whereas the reduced B-memory cell and plasma blast generation could be related to fast Ab decline with a limited maintenance of titers. Among T follicular helper cell (Tfh) cells, the Tfh17 subset was significantly expanded particularly in obese males, where we observed a strong initial Ab increase. Systemic but not local vaccine side effects were more frequent in obese subjects as a possible consequence of their low-grade proinflammatory state. In summary, TBE booster vaccination was effective in obese individuals, yet the faster Ab decline could result in a reduced long-term protection. The sex-based differences in vaccine responses indicate a complex interplay of the endocrine, metabolic, and immune system during obesity. Further studies on the long-term protection after vaccination are ongoing, and also evaluation of primary vaccination against TBE in obese individuals is planned.

Clinical Trial Registration: NCT04017052; https://clinicaltrials.gov/ct2/show/NCT04017052.

Pregnancy has a minimal impact on the acute transcriptional signature to vaccination

Vaccination in pregnancy is an effective tool to protect both the mother and infant; vaccines against influenza, pertussis and tetanus are currently recommended. A number of vaccines with a specific indication for use in pregnancy are in development, with the specific aim of providing passive humoral immunity to the newborn child against pathogens responsible for morbidity and mortality in young infants. However, the current understanding about the immune response to vaccination in pregnancy is incomplete. We analysed the effect of pregnancy on early transcriptional responses to vaccination. This type of systems vaccinology approach identifies genes and pathways that are altered in response to vaccination and can be used to understand both the acute inflammation in response to the vaccine and to predict immunogenicity. Pregnant women and mice were immunised with Boostrix-IPV, a multivalent vaccine, which contains three pertussis antigens. Blood was collected from women before and after vaccination and RNA extracted for analysis by microarray. While there were baseline differences between pregnant and non-pregnant women, vaccination induced characteristic patterns of gene expression, with upregulation in interferon response and innate immunity gene modules, independent of pregnancy. We saw similar patterns of responses in both women and mice, supporting the use of mice for preclinical screening of novel maternal vaccines. Using a systems vaccinology approach in pregnancy demonstrated that pregnancy does not affect the initial response to vaccination and that studies in non-pregnant women can provide information about vaccine immunogenicity and potentially safety.

Toward precision adjuvants: optimizing science and safety

PURPOSE OF REVIEW

The gradual replacement of inactivated whole cell and live attenuated vaccines with subunit vaccines has generally reduced reactogenicity but in many cases also immunogenicity. Although only used when necessary, adjuvants can be key to vaccine dose/antigen-sparing, broadening immune responses to variable antigens, and enhancing immunogenicity in vulnerable populations with distinct immunity. Licensed vaccines contain an increasing variety of adjuvants, with a growing pipeline of adjuvanted vaccines under development.

RECENT FINDINGS

Most adjuvants, including Alum, Toll-like receptor agonists and oil-in-water emulsions, activate innate immunity thereby altering the quantity and quality of an adaptive immune response. Adjuvants activate leukocytes, and induce mediators (e.g., cytokines, chemokines, and prostaglandin-E2) some of which are biomarkers for reactogenicity, that is, induction of local/systemic side effects. Although there have been safety concerns regarding a hypothetical risk of adjuvants inducing auto-immunity, such associations have not been established. As immune responses vary by population (e.g., age and sex), adjuvant research now incorporates principles of precision medicine. Innovations in adjuvant research include use of human in vitro models, immuno-engineering, novel delivery systems, and systems biology to identify biomarkers of safety and adjuvanticity.

SUMMARY

Adjuvants enhance vaccine immunogenicity and can be associated with reactogenicity. Novel multidisciplinary approaches hold promise to accelerate and de-risk targeted adjuvant discovery and development. VIDEO ABSTRACT: http://links.lww.com/MOP/A53.

Characterization of potential biomarkers of reactogenicity of licensed antiviral vaccines: randomized controlled clinical trials conducted by the BIOVACSAFE consortium

Biomarkers predictive of inflammatory events post-vaccination could accelerate vaccine development. Within the BIOVACSAFE framework, we conducted three identically designed, placebo-controlled inpatient/outpatient clinical studies (NCT01765413/NCT01771354/NCT01771367). Six antiviral vaccination strategies were evaluated to generate training data-sets of pre-/post-vaccination vital signs, blood changes and whole-blood gene transcripts, and to identify putative biomarkers of early inflammation/reactogenicity that could guide the design of subsequent focused confirmatory studies. Healthy adults (N = 123; 20-21/group) received one immunization at Day (D)0. Alum-adjuvanted hepatitis B vaccine elicited vital signs and inflammatory (CRP/innate cells) responses that were similar between primed/naive vaccinees, and low-level gene responses. MF59-adjuvanted trivalent influenza vaccine (ATIV) induced distinct physiological (temperature/heart rate/reactogenicity) response-patterns not seen with non-adjuvanted TIV or with the other vaccines. ATIV also elicited robust early (D1) activation of IFN-related genes (associated with serum IP-10 levels) and innate-cell-related genes, and changes in monocyte/neutrophil/lymphocyte counts, while TIV elicited similar but lower responses. Due to viral replication kinetics, innate gene activation by live yellow-fever or varicella-zoster virus (YFV/VZV) vaccines was more suspended, with early IFN-associated responses in naïve YFV-vaccine recipients but not in primed VZV-vaccine recipients. Inflammatory responses (physiological/serum markers, innate-signaling transcripts) are therefore a function of the vaccine type/composition and presence/absence of immune memory. The data reported here have guided the design of confirmatory Phase IV trials using ATIV to provide tools to identify inflammatory or reactogenicity biomarkers.

Combining immunoprofiling with machine learning to assess the effects of adjuvant formulation on human vaccine-induced immunity

Adjuvants produce complex, but often subtle, effects on vaccine-induced immune responses that, nonetheless, play a critical role in vaccine efficacy. In-depth profiling of vaccine-induced cytokine, cellular, and antibody responses ("immunoprofiling") combined with machine-learning holds the promise of identifying adjuvant-specific immune response characteristics that can guide rational adjuvant selection. Here, we profiled human immune responses induced by vaccines adjuvanted with two similar, clinically relevant adjuvants, AS01B and AS02A, and identified key distinguishing characteristics, or immune signatures, they imprint on vaccine-induced immunity. Samples for this side-by-side comparison were from malaria-naïve individuals who had received a recombinant malaria subunit vaccine (AMA-1) that targets the pre-erythrocytic stage of the parasite. Both adjuvant formulations contain the same immunostimulatory components, QS21 and MPL, thus this study reveals the subtle impact that adjuvant formulation has on immunogenicity. Adjuvant-mediated immune signatures were established through a two-step approach: First, we generated a broad immunoprofile (serological, functional and cellular characterization of vaccine-induced responses). Second, we integrated the immunoprofiling data and identify what combination of immune features was most clearly able to distinguish vaccine-induced responses by adjuvant using machine learning. The computational analysis revealed statistically significant differences in cellular and antibody responses between cohorts and identified a combination of immune features that was able to distinguish subjects by adjuvant with 71% accuracy. Moreover, the in-depth characterization demonstrated an unexpected induction of CD8⁺ T cells by the recombinant subunit vaccine, which is rare and highly relevant for future vaccine design.

The how's and what's of vaccine reactogenicity

Reactogenicity represents the physical manifestation of the inflammatory response to vaccination, and can include injection-site pain, redness, swelling or induration at the injection site, as well as systemic symptoms, such as fever, myalgia, or headache. The experience of symptoms following vaccination can lead to needle fear, long-term negative attitudes and non-compliant behaviours, which undermine the public health impact of vaccination. This review presents current knowledge on the potential causes of reactogenicity, and how host characteristics, vaccine administration and composition factors can influence the development and perception of reactogenicity. The intent is to provide an overview of reactogenicity after vaccination to help the vaccine community, including healthcare professionals, in maintaining confidence in vaccines by promoting vaccination, setting expectations for vaccinees about what might occur after vaccination and reducing anxiety by managing the vaccination setting.

PlatformTM, a standards-based data custodianship platform for translational medicine research

Biomedical informatics has traditionally adopted a linear view of the informatics process (collect, store and analyse) in translational medicine (TM) studies; focusing primarily on the challenges in data integration and analysis. However, a data management challenge presents itself with the new lifecycle view of data emphasized by the recent calls for data re-use, long term data preservation, and data sharing. There is currently a lack of dedicated infrastructure focused on the 'manageability' of the data lifecycle in TM research between data collection and analysis. Current community efforts towards establishing a culture for open science prompt the creation of a data custodianship environment for management of TM data assets to support data reuse and reproducibility of research results. Here we present the development of a lifecycle-based methodology to create a metadata management framework based on community driven standards for standardisation, consolidation and integration of TM research data. Based on this framework, we also present the development of a new platform (PlatformTM) focused on managing the lifecycle for translational research data assets.

Adjuvant Systems for vaccines: 13 years of post-licensure experience in diverse populations have progressed the way adjuvanted vaccine safety is investigated and understood

Adjuvant Systems (AS) are combinations of immune stimulants that enhance the immune response to vaccine antigens. The first vaccine containing an AS (AS04) was licensed in 2005. As of 2018, several vaccines containing AS04, AS03 or AS01 have been licensed or approved by regulatory authorities in some countries, and included in vaccination programs. These vaccines target diverse viral and parasitic diseases (hepatitis B, human papillomavirus, malaria, herpes zoster, and (pre)pandemic influenza), and were developed for widely different target populations (e.g. individuals with renal impairment, girls and young women, infants and children living in Africa, adults 50 years of age and older, and the general population). Clearly, the safety profile of one vaccine in one target population cannot be extrapolated to another vaccine or to another target population, even for vaccines containing the same adjuvant. Therefore, the assessment of adjuvant safety poses specific challenges. In this review we provide a historical perspective on how AS were developed from the angle of the challenges encountered on safety evaluation during clinical development and after licensure, and illustrate how these challenges have been met to date. Methods to evaluate safety of adjuvants have evolved based on the availability of new technologies allowing a better understanding of their mode of action, and new ways of collecting and assessing safety information. Since 2005, safety experience with AS has accumulated with their use in diverse vaccines and in markedly different populations, in national immunization programs, and in a pandemic setting. Thirteen years of experience using antigens combined with AS attest to their acceptable safety profile. Methods developed to assess the safety of vaccines containing AS have progressed the way we understand and investigate vaccine safety, and have helped set new standards that will guide and support new candidate vaccine development, particularly those using new adjuvants. FOCUS ON THE PATIENT: What is the context? Adjuvants are immunostimulants used to modulate and enhance the immune response induced by vaccination. Since the 1990s, adjuvantation has moved toward combining several immunostimulants in the form of Adjuvant System(s) (AS), rather than relying on a single immunostimulant. AS have enabled the development of new vaccines targeting diseases and/or populations with special challenges that were previously not feasible using classical vaccine technology. What is new? In the last 13 years, several AS-containing vaccines have been studied targeting different diseases and populations. Over this period, overall vaccine safety has been monitored and real-life safety profiles have been assessed following routine use in the general population in many countries. Moreover, new methods for safety assessment, such as a better determination of the mode of action, have been implemented in order to help understand the safety characteristics of AS-containing vaccines. What is the impact? New standards and safety experience accumulated over the last decade can guide and help support the safety assessment of new candidate vaccines during development.

Inflammatory parameters associated with systemic reactogenicity following vaccination with adjuvanted hepatitis B vaccines in humans

BACKGROUND

Adjuvants like AS01_B increase the immunogenicity of vaccines and generally cause increased transient reactogenicity compared with Alum. A phase II randomized trial was conducted to characterize the response to AS01_B and Alum adjuvanted vaccines. A post-hoc analysis was performed to examine the associations between reactogenicity and innate immune parameters.

METHODS

The trial involved 60 hepatitis B-naïve adults aged 18-45 years randomized 1:1 to receive either two doses of HBsAg-AS01_B on Day (D)0 and D30, or three doses of HBsAg-Alum on D0, D30, D180. Prior to vaccination, all subjects received placebo injection in order to differentiate the impact of injection process and the vaccination. Main outcomes included reactogenicity symptoms, vital signs, blood cytokines, biochemical and hematological parameters after vaccination. Associations were explored using linear regression.

FINDINGS

The vaccine with AS01_B induced higher HBsAg-specific antibody levels than Alum. Local and systemic symptoms were more frequent in individuals who received HBsAg AS01_B/Alum vaccine or placebo, but were mild and short-lived. Blood levels of C-reactive protein (CRP), bilirubin, leukocyte, monocyte and neutrophil counts increased rapidly and transiently after AS01_B but not after Alum or placebo. Lymphocyte counts decreased in the AS01_B group and lactate dehydrogenase levels decreased after Alum. Modelling revealed associations between systemic symptoms and increased levels of CRP and IL-6 after the first HBsAg-AS01_B or HBsAg-Alum immunization. Following the second vaccine dose, CRP, IL-6, IP-10, IFN-γ, MIP-1β and MCP-2 were identified as key parameters associated with systemic symptoms. These observations were confirmed using an independent data set extracted from a previous study of the immune response to HBsAg-adjuvanted vaccines (NCT00805389).

CONCLUSIONS

IL-6 and IFN-γ signals were associated with systemic reactogenicity following administration of AS01_B-adjuvanted vaccine. These signals were similar to those previously associated with antibody and T-cell responses induced by HBsAg-adjuvanted vaccines, suggesting that similar innate immune signals may underlie adjuvant reactogenicity and immunogenicity.

TRIAL REGISTRATION

www.clinicaltrials.gov NCT01777295.

Systems vaccinology and big data in the vaccine development chain

Systems vaccinology has proven a fascinating development in the last decade. Where traditionally vaccine development has been dominated by trial and error, systems vaccinology is a tool that provides novel and comprehensive understanding if properly used. Data sets retrieved from systems‐based studies endorse rational design and effective development of safe and efficacious vaccines. In this review we first describe different omics‐techniques that form the pillars of systems vaccinology. In the second part, the application of systems vaccinology in the different stages of vaccine development is described. Overall, this review shows that systems vaccinology has become an important tool anywhere in the vaccine development chain.

Will Systems Biology Deliver Its Promise and Contribute to the Development of New or Improved Vaccines? Systems Biology Views of Vaccine Innate and Adaptive Immunity

During the last decade, several high-throughput technologies have been applied to gather deeper understanding on the biological events elicited by vaccination. The main goal of systems biology is to integrate different sources of data and extract biologically meaningful information. This holistic approach has provided new insights on the impact that the innate immune status has on vaccine responsiveness. Other factors like chronic infections, age, microbiome, and metabolism can influence the outcome of vaccination, and systems biology offers unique opportunities to expand our understanding of their role on the immune response. However, a few challenges that still need to be overcome will be discussed.

Type III hypersensitivity reactions to a B cell epitope antigen are abrogated using a depot forming vaccine platform

Peptide antigens are combined with an adjuvant in order to increase immunogenicity in vivo. The immunogenicity and safety of a RSV vaccine formulated in a novel oil-based platform, DepoVax™ (DPX), was compared to an alum formulation. A peptide B cell epitope derived from RSV small hydrophobic ectodomain (SHe) served as the antigen. Both vaccines induced SHe-specific antibodies after immunization of mice. A single dose of the DPX-based formulation resulted in anti-SHe titres for up to 20 weeks. Boosting with Alum-SHe, but not with DPX-SHe, led to unexpected clinical signs such as decreased activity, cyanosis and drop in body temperature in mice but not in rabbits. The severity of adverse reactions correlated with magnitude of SHe-specific IgG immune responses and decreased complement component 3 plasma levels, indicating a type III hypersensitivity reaction. By RP-HPLC analysis, we found that only 8-20% of the antigen was found to be adsorbed to alum in vitro, indicating that this antigen is likely released systemically upon injection in vivo. Clinical signs were not observed in rabbits, indicating the response correlates with peptide dose relative to size of animal. These results suggest that peptide antigens targeted to produce B cell mediated response may result in increased incidence of type III hypersensitivity reactions when delivered in non-depot forming vaccines. The DPX formulation induced strong antibody titres to the antigen without causing adverse events, likely due to the strength of the depot in vivo, and demonstrates the potential safety and immunogenicity of this platform for B cell peptide antigens.

Novel approaches in preclinical HIV vaccine research

PURPOSE OF REVIEW

The purpose is to review recent novel approaches in HIV vaccine research and development being undertaken in the preclinical and early clinical space, as well as related and novel nonvaccine approaches such as genetic delivery of broadly neutralizing antibodies for protection from HIV infection and AIDS.

RECENT FINDINGS

We review novel HIV envelope immunogen design, including native trimer and germline targeting approaches as well as genetic delivery of broadly neutralizing antibodies and replicating vector vaccinesSUMMARY: Despite 30+ years of research and development, and billions of dollars spent, a well tolerated and effective HIV vaccine remains a public health priority for any chance of ending the AIDS pandemic. It has become very clear that significant investments in novel technologies, innovation, and multidisciplinary science will be necessary to accelerate progress.

The synergistic effects of combining TLR ligand based adjuvants on the cytokine response are dependent upon p38/JNK signalling

Toll like receptor (TLR) ligands are important adjuvant candidates, causing antigen presenting cells to release inflammatory mediators, leading to the recruitment and activation of other leukocytes. The aim of this study was to define the response of human blood derived dendritic cells and macrophages to three TLR ligands acting singly or in combination, Poly I:C (TLR3), GLA (TLR4) and R848 (TLR7/8). Combinations of TLR agonists have been shown to have a synergistic effect on individual cytokines, here we look at the global inflammatory response measuring both cytokines and chemokines. Using a custom Luminex assay we saw dose responses in several mediators including CCL3 (MIP1α), IL-1α, IL-1β, IL-12, CXCL10 (IP-10) and IL-6, all of which were significantly increased by the combination of R848 and GLA, even when low dose GLA was added. The synergistic effect was inhibited by specific MAP kinase inhibitors blocking the kinases p38 and JNK but not MEK1. Combining TLR adjuvants also had a synergistic effect on cytokine responses in human mucosal tissue explants. From this we conclude that the combination of R848 and GLA potentiates the inflammatory profile of antigen presenting cells. Since the pattern of inflammatory mediators released can alter the quality and quantity of the adaptive immune response to vaccination, this study informs vaccine adjuvant design.

Regulatory T cell frequencies and phenotypes following anti-viral vaccination

Regulatory T cells (Treg) function in the prevention of excessive inflammation and maintenance of immunological homeostasis. However, these cells may also interfere with resolution of infections or with immune reactions following vaccination. Effects of Treg on vaccine responses are nowadays investigated, but the impact of vaccination on Treg homeostasis is still largely unknown. This may be a relevant safety aspect, since loss of tolerance through reduced Treg may trigger autoimmunity. In exploratory clinical trials, healthy adults were vaccinated with an influenza subunit vaccine plus or minus the adjuvant MF59®, an adjuvanted hepatitis B subunit vaccine or a live attenuated yellow fever vaccine. Frequencies and phenotypes of resting (rTreg) and activated (aTreg) subpopulations of circulating CD4+ Treg were determined and compared to placebo immunization. Vaccination with influenza vaccines did not result in significant changes in Treg frequencies and phenotypes. Vaccination with the hepatitis B vaccine led to slightly increased frequencies of both rTreg and aTreg subpopulations and a decrease in expression of functionality marker CD39 on aTreg. The live attenuated vaccine resulted in a decrease in rTreg frequency, and an increase in expression of activation marker CD25 on both subpopulations, possibly indicating a conversion from resting to migratory aTreg due to vaccine virus replication. To study the more local effects of vaccination on Treg in lymphoid organs, we immunized mice and analyzed the CD4+ Treg frequency and phenotype in draining lymph nodes and spleen. Vaccination resulted in a transient local decrease in Treg frequency in lymph nodes, followed by a systemic Treg increase in the spleen. Taken together, we showed that vaccination with vaccines with an already established safe profile have only minimal impact on frequencies and characteristics of Treg over time. These findings may serve as a bench-mark of inter-individual variation of Treg frequencies and phenotypes following vaccination.

Inflammatory responses to influenza vaccination at the extremes of age

Age affects the immune response to vaccination, with individuals at the extremes of age responding poorly. The initial inflammatory response to antigenic materials shapes the subsequent adaptive response and so understanding is required about the effect of age on the profile of acute inflammatory mediators. In this study we measured the local and systemic inflammatory response after influenza vaccination or infection in neonatal, young adult and aged mice. Mice were immunized intramuscularly with inactivated influenza vaccine with and without the adjuvant MF59 and then challenged with H1N1 influenza. Age was the major factor affecting the inflammatory profile after vaccination: neonatal mice had more interleukin-1α (IL-1α), C-reactive protein (CRP) and granulocyte-macrophage colony-stimulating factor (GMCSF), young adults more tumour necrosis factor-α (TNF), and elderly mice more interleukin-1 receptor antagonist (IL-1RA), IL-2RA and interferon-γ-induced protein 10 (IP10). Notably the addition of MF59 induced IL-5, granulocyte colony-stimulating factor (G-CSF), Keratinocyte Chemotractant (KC) and monocyte chemoattractant protein 1 (MCP1) in all ages of animals and levels of these cytokines correlated with antibody responses. Age also had an impact on the efficacy of vaccination: neonatal and young adult mice were protected against challenge, but aged mice were not. There were striking differences in the localization of the cytokine response depending on the route of exposure: vaccination led to a high serum response whereas intranasal infection led to a low serum response but a high lung response. In conclusion, we demonstrate that age affects the inflammatory response to both influenza vaccination and infection. These age-induced differences need to be considered when developing vaccination strategies for different age groups.

Distinct Antigen Delivery Systems Induce Dendritic Cells' Divergent Transcriptional Response: New Insights from a Comparative and Reproducible Computational Analysis

Vaccination is the most successful and cost-effective method to prevent infectious diseases. However, many vaccine antigens have poor in vivo immunogenic potential and need adjuvants to enhance immune response. The application of systems biology to immunity and vaccinology has yielded crucial insights about how vaccines and adjuvants work. We have previously characterized two safe and powerful delivery systems derived from non-pathogenic prokaryotic organisms: E2 and fd filamentous bacteriophage systems. They elicit an in vivo immune response inducing CD8+ T-cell responses, even in absence of adjuvants or stimuli for dendritic cells’ maturation. Nonetheless, a systematic and comparative analysis of the complex gene expression network underlying such activation is missing. Therefore, we compared the transcriptomes of ex vivo isolated bone marrow-derived dendritic cells exposed to these antigen delivery systems. Significant differences emerged, especially for genes involved in innate immunity, co-stimulation, and cytokine production. Results indicate that E2 drives polarization toward the Th2 phenotype, mainly mediated by Irf4, Ccl17, and Ccr4 over-expression. Conversely, fd-scαDEC-205 triggers Th1 T cells’ polarization through the induction of Il12b, Il12rb, Il6, and other molecules involved in its signal transduction. The data analysis was performed using RNASeqGUI, hence, addressing the increasing need of transparency and reproducibility of computational analysis.

A Meningococcal Outer Membrane Vesicle Vaccine Incorporating Genetically Attenuated Endotoxin Dissociates Inflammation from Immunogenicity

Background

Group B Neisseria meningitidis, an endotoxin-producing Gram-negative bacterium, causes the highest incidence of group B meningococcus (MenB) disease in the first year of life. The Bexsero vaccine is indicated in Europe from 8 weeks of age. Endotoxin components of outer membrane vesicles (OMVs) or soluble lipopolysaccharide (LPS) represent a potential source of inflammation and residual reactogenicity. The purpose of this study was to compare novel candidate MenB vaccine formulations with licensed vaccines, including Bexsero, using age-specific human in vitro culture systems.

Methods

OMVs from wild type- and inactivated lpxL1 gene mutant-N. meningitidis strains were characterized in human neonatal and adult in vitro whole blood assays and dendritic cell (DC) arrays. OMVs were benchmarked against licensed vaccines, including Bexsero and whole cell pertussis formulations, with respect to Th-polarizing cytokine and prostaglandin E2 production, as well as cell surface activation markers (HLA-DR, CD86, and CCR7). OMV immunogenicity was assessed in mice.

Results

ΔlpxLI native OMVs (nOMVs) demonstrated significantly less cytokine induction in human blood and DCs than Bexsero and most of the other pediatric vaccines (e.g., PedvaxHib, EasyFive, and bacillus Calmette–Guérin) tested. Despite a much lower inflammatory profile in vitro than Bexsero, ΔlpxLI nOMVs still had moderate DC maturing ability and induced robust anti-N. meningitidis antibody responses after murine immunization.

Conclusion

A meningococcal vaccine comprised of attenuated LPS-based OMVs with a limited inflammatory profile in vitro induces robust antigen-specific immunogenicity in vivo.

Early Rise of Blood T Follicular Helper Cell Subsets and Baseline Immunity as Predictors of Persisting Late Functional Antibody Responses to Vaccination in Humans

CD4⁺ T follicular helper cells (T_FH) have been identified as the T-cell subset specialized in providing help to B cells for optimal activation and production of high affinity antibody. We recently demonstrated that the expansion of peripheral blood influenza-specific CD4⁺IL-21⁺ICOS1⁺ T helper (T_H) cells, three weeks after vaccination, associated with and predicted the rise of protective neutralizing antibodies to avian H5N1. In this study, healthy adults were vaccinated with plain seasonal trivalent inactivated influenza vaccine (TIIV), MF59^®-adjuvanted TIIV (ATIIV), or saline placebo. Frequencies of circulating CD4⁺ T_FH1 ICOS⁺ T_FH cells and H1N1-specific CD4⁺IL-21⁺ICOS⁺ CXCR5⁺ T_FH and CXCR5^- T_H cell subsets were determined at various time points after vaccination and were then correlated with hemagglutination inhibition (HI) titers. All three CD4+ T cell subsets expanded in response to TIIV and ATIIV, and peaked 7 days after vaccination. To demonstrate that these T_FH cell subsets correlated with functional antibody titers, we defined an alternative endpoint metric, decorrelated HI (DHI), which removed any correlation between day 28/day 168 and day 0 HI titers, to control for the effect of preexisting immunity to influenza vaccine strains. The numbers of total circulating CD4⁺ T_FH1 ICOS⁺ cells and of H1N1-specific CD4⁺IL-21⁺ICOS⁺ CXCR5⁺, measured at day 7, were significantly associated with day 28, and day 28 and 168 DHI titers, respectively. Altogether, our results show that CD4⁺ T_FH subsets may represent valuable biomarkers of vaccine-induced long-term functional immunity.

Use of the Microparticle Nanoscale Silicon Dioxide as an Adjuvant To Boost Vaccine Immune Responses against Influenza Virus in Neonatal Mice

Neonates are at a high risk of infection, but vaccines are less effective in this age group; tailored adjuvants could potentially improve vaccine efficacy. Increased understanding about danger sensing by the innate immune system has led to the rational design of novel adjuvants. But differences in the neonatal innate immune response, for example, to Toll-like receptor (TLR) agonists, can reduce the efficacy of these adjuvants in early life. We therefore targeted alternative danger-sensing pathways, focusing on a range of compounds described as inflammasome agonists, including nanoscale silicon dioxide (NanoSiO2), calcium pyrophosphate dihydrate (CPPD) crystals, and muramyl tripeptide (M-Tri-DAP), for their ability to act as adjuvants.In vitro, these compounds induced an interleukin 1-beta (IL-1β) response in the macrophage-like cell line THP1.In vivo, adult CB6F1 female mice were immunized intramuscularly with H1N1 influenza vaccine antigens in combination with NanoSiO2, CPPD, or M-Tri-DAP and subsequently challenged with H1N1 influenza virus (A/England/195/2009). The adjuvants boosted anti-hemagglutinin IgG and IgA antibody levels. Both adult and neonatal animals that received NanoSiO2-adjuvanted vaccines lost significantly less weight and recovered earlier after infection than control animals treated with antigen alone. Administration of the adjuvants led to an influx of activated inflammatory cells into the muscle but to little systemic inflammation measured by serum cytokine levels. Blocking IL-1β or caspase 1 in vivo had little effect on NanoSiO2 adjuvant function, suggesting that it may work through pathways other than the inflammasome. Here we demonstrate that NanoSiO2 can act as an adjuvant and is effective in early life.

IMPORTANCE

Vaccines can fail to protect the most at-risk populations, including the very young, the elderly, and the immunocompromised. There is a gap in neonatal immunity between the waning of maternal protection and routine infant immunization schedules, exacerbated by the failure of vaccines to work in the first months of life. One approach is to design age-specific formulations, with more-effective adjuvants, based on our understanding of the nature of the neonatal immune response. We chose to target the inflammasome, a molecular complex capable of detecting infection and cell damage and of triggering IL-1β-driven inflammation. We screened a range of compounds in vitro and in vivo and identified three lead candidates: NanoSiO2, CPPD, and M-Tri-DAP. Of these, NanoSiO2 was the most effective and boosted the anti-influenza virus response in both adult and neonatal mice. This finding is important for the development of age-specific vaccines, designed using our knowledge of the neonatal immune response.

Development of a custom pentaplex sandwich immunoassay using Protein-G coupled beads for the Luminex® xMAP® platform

Multiplex bead-based assays have many advantages over ELISA, particularly for the analyses of large quantities of samples and/or precious samples of limited volume. Although many commercial arrays covering multitudes of biologically significant analytes are available, occasionally the development of custom arrays is necessary. Here, the development of a custom pentaplex sandwich immunoassay using Protein G-coupled beads, for analysis using the Luminex® xMAP® platform, is described. This array was required for the measurement of candidate biomarkers of vaccine safety in small volumes of mouse sera. Optimisation of this assay required a stepwise approach: testing cross-reactivity of the antibody pairs, the development of an in-house serum diluent buffer as well as heat-inactivation of serum samples to prevent interference from matrix effects. We then demonstrate the use of this array to analyse inflammatory mediators in mouse serum after immunisation. The work described here exemplifies how Protein G-coupled beads offer a flexible and robust approach to develop custom multiplex immunoassays, which can be applied to a range of analytes from multiple species.