Vaccine Components Research Articles

Immunogenicity and Efficacy of Combined mRNA Vaccine Against Influenza and SARS-CoV-2 in Mice Animal Models

Background. The combined or multivalent vaccines are actively used in pediatric practice and offer a series of advantages, including a reduced number of injections and visits to the doctor, simplicity of the vaccination schedule and minimization of side effects, easier vaccine monitoring and storage, and lower vaccination costs. The practice of widespread use of the combined vaccines has shown the potential to increase vaccination coverage against single infections. The mRNA platform has been shown to be effective against the COVID-19 pandemic and enables the development of combined vaccines. There are currently no mRNA-based combined vaccines approved for use in humans. Some studies have shown that different mRNA components in a vaccine can interact to increase or decrease the immunogenicity and efficacy of the combined vaccine. Objectives. In the present study, we investigated the possibility of combining the mRNA vaccines, encoding seasonal influenza and SARS-CoV-2 antigens. In our previous works, both vaccine candidates have shown excellent immunogenicity and efficacy profiles in mice. Methods. The mRNA-LNPs were prepared by microfluidic mixing, immunogenicity in mice was assessed by hemagglutination inhibition assay, enzyme-linked immunoassay and virus neutralization assay. Immunological efficacy was assessed in a mouse viral challenge model. Results. In this work, we demonstrated that the individual mRNA components of the combined vaccine did not affect the immunogenicity level of each other. The combined vaccine demonstrated excellent protective efficacy, providing a 100% survival rate when mice were infected with the H1N1 influenza virus and reducing the viral load in the lungs. Four days after the challenge with SARS-CoV-2 EG.5.1.1., no viable virus and low levels of detectable viral RNA were observed in the lungs of vaccinated mice. Conclusions. The combination does not lead to mutual interference between the individual vaccines. We believe that such a combined mRNA-based vaccine could be a good alternative to separated human vaccinations for the prevention of COVID-19 and influenza.

Antibody responses to re-immunization in recipients of allogeneic hematopoietic cell transplantation

Abstract Background Immunologic memory against vaccine-preventable diseases is often lost after an allogeneic hematopoietic cell transplant (allo-HCT), therefore recipients are required to be re-immunized after allo-HCT to regain immunity against these infections. But the response to vaccination after an allo-HCT can be highly variable and is not well understood. We performed a single center retrospective study to examine immunization practices and determine the rate of vaccine protection and seroconversion following vaccination after allo-HCT. Methods Electronic medical records (EMR) from patients ≤18 years of age who underwent allo-HCT at St. Jude Childrens’ Research Hospital between 2005 - 2021 were reviewed. Clinical information and serology results before and after completion of the immunizations series were extracted from the EMR. The vaccines included in this analysis were diphtheria, measles, mumps, rubella (MMR), varicella, and polio. Protection was evaluated only for infections with established immune correlates. Seroconversion was defined as 4-fold increase in titers for vaccines with quantitative antibody assays, or as a change from negative to positive IgG for vaccines with qualitative antibody tests. Results 760 patients were included in this cohort. Demographic and clinical data are summarized in Table 1. The mean age at allo-HCT was 10.4 years, most were male (56.8%) and white (74.6%). Acute leukemia accounted for 66.4% of allo-HCT recipients. Conditioning was myeloablative for 53.45%, and reduced intensity for 37.9%. Most received transplants from mismatched-related donors, (44.9%), followed by matched unrelated donors (35.4%) and matched related donors (19.5%). The number of patients who received the full vaccination series at our institution differed by vaccine and ranged from 41-150, and the respective subsets with available pre-vaccination and post-vaccination titers ranged from 24-93. The median time from transplant to initiation of immunizations was 12 months (range: 6-58) for non-live vaccines, 25 months (range: 23, 63) for MMR vaccine, and 28 months (range: 16, 117)) for varicella vaccine. Protection post immunization varied, with less patients demonstrating protections for mumps (79%) and measles (82%) (Figure 1). Seroconversion also varied among the different vaccine components and types of vaccines. Conclusion Current strategies to re-immunize patients after allo-HCT do not provide protection to all patients. Understanding the factors associated with suboptimal immune responses is critical for advancing our knowledge in this area. Whether time-based approaches combined with immune reconstitution data are required to further optimize protection remains unclear. Additionally, different vaccine schedules (i.e., higher doses) may be required in these patients. Figure 1. Protection and seroconversion rate by vaccine target.

Mono-palmitoyl-N-alkylurea ligands as specific activators of human Toll-like receptor 2/6 heterodimer.

Ligands for Toll-like-receptor 2 (TLR2) have demonstrated significant potential as immune-stimulating components in synthetic vaccines. Activation of TLR2 relies on the formation of dimeric complexes with either TLR1 or TLR6 and the nature of these dimers can impact therapeutic outcomes. The lipopeptide-based TLR2 ligands Pam3CysSK4 and Pam2CysSK4 have been extensively studied, and their recognition by different TLR-receptor heterodimers, TLR2/TLR1 and TLR2/TLR6, respectively, has been established. However, the high lipophilicity of these ligands, containing multiple palmitoyl residues, can result in solubility issues when used as vaccine adjuvants. To address this, we previously synthesized a less lipophilic ligand containing a single palmitoyl chain called mini-UPam, which effectively stimulates human moDC maturation. We here probe the receptor-dimer specificity of several mini-Upam derivatives and reveal that these mini-UPam are hTLR2/TLR6 selective ligands and that the introduction of longer urea alkyl chains does not shift the binding specificity to hTLR2/TLR1 heterodimers, in contrast to their Pam2CysSK4 and Pam3CysSK4 counterparts, pointing to a different binding mode of the UPam ligands.

A Phase II/III multicenter randomized single blind non-inferiority immunogenicity and safety study of TeddyVac™ vaccine of Human Biologicals Institute in healthy subjects of 10 years to 60 years of age

Background WHO and other health agencies recommend that tetanus toxoid (TT) should be replaced by tetanus-diphtheria (Td) vaccine taking into consideration the low coverage and waning immunity, especially for diphtheria. In this randomised, multicentre, non-inferiority study, the immunogenicity and safety of TeddyVac™ vaccine of Human Biologicals Institute were compared with an existing brand. Methods The study involved 444 eligible subjects in two age groups at four centres across India. Group A included subjects of 18–60 years and Group B subjects of 10–18 years of age. All subjects received single dose of either TeddyVac™ or the comparator vaccine as per randomisation. Blood samples for antibody titre estimation were collected before vaccination and 4–6 weeks after vaccination. Immunogenicity was assessed by estimating seroconversion rate, seroprotection rate, and geometric mean titres of antibodies. Safety was evaluated by collection and analysis of data on solicited and unsolicited adverse events. Results Overall, 441 subjects completed the study. Both the vaccine arms showed comparable seroconversion after a single dose for both the components. Both arms showed increase in seroprotection and geometric mean titres after a single dose of vaccination for both vaccine components, being significantly better for the diphtheria component in the test vaccine arm. Only few minor local and systemic adverse events were observed in both the vaccine arms. No serious adverse event was reported. Conclusion The study results indicate that the TeddyVac™ vaccine is immunogenic, safe and non-inferior to the comparator Vaccine when administered to healthy subjects of 10 to 60 years of age. CTRI Registration number CTRI/2021/07/035112

Modified Hemocyanins from Rapana thomasiana and Helix aspersa Exhibit Strong Antitumor Activity in the B16F10 Mouse Melanoma Model.

Melanoma is one of the most common tumors worldwide, and new approaches and antitumor drugs for therapy are being investigated. Among the promising biomolecules of natural origin for antitumor research are gastropodan hemocyanins-highly immunogenic multimeric glycoproteins used as antitumor agents and components of therapeutic vaccines in human and mouse cancer models. A murine melanoma model established in C57BL/6 mice of the B16F10 cell line was used to study anticancer modified oxidized hemocyanins (Ox-Hcs) that were administered to experimental animals (100 μg/mouse) under different regimens: mild, intensive, and with sensitization. The solid tumor growth, antitumor response, cell infiltration in tumors, and survival were assessed using flow cytometry, ELISA, and cytotoxicity assays. Therapy with Ox-RtH or Ox-HaH resulted in the generation of enhanced specific immune response (increased levels of tumor-infiltrated mature NK cells (CD27+CD11b+) in sensitized groups and of macrophages in the intensively immunized animals) and tumor suppression. Beneficial effects such as delayed tumor incidence and growth as well as prolonged survival of tumor-bearing animals have been observed. High levels of melanoma-specific CTLs that mediate cytotoxic effects on tumor cells; tumor-infiltrating IgM antibodies expected to enhance antibody-dependent cellular cytotoxicity; type M1 macrophages, which stimulate the Th1 response and cytotoxic cells; and proinflammatory cytokines, were also observed after Ox-Hcs administration. The modified Hcs showed strong antitumor properties in different administration regimens in a murine model of melanoma with potential for future application in humans.

Safety of a 4-Dose 20-Valent Pneumococcal Conjugate Vaccine Series in Infants: A Randomized Trial.

The 20-valent pneumococcal conjugate vaccine (PCV20) was developed to expand protection for pneumococcal disease. It contains all 13-valent pneumococcal conjugate vaccine (PCV13) components plus conjugates for 7 additional serotypes. Our primary objective with this study was to evaluate PCV20 tolerability and safety. In this phase 3, multi-country, double-blind study, healthy infants born at ≥34 weeks' gestation were randomly assigned 2:1 to receive PCV20 or PCV13 at 2, 4, 6, and 12 to 15 months of age. Safety assessments included local reactions and systemic events within 7 days after each vaccination, adverse events (AEs) from dose 1 to 1 month after dose 3 and from dose 4 to 1 month after dose 4, and serious AEs and newly diagnosed chronic medical conditions from dose 1 through 6 months after the last dose. Participants received PCV20 (N = 1000) or PCV13 (N = 504); 91.7% received all 4 doses. The frequencies of local reactions and systemic events were generally similar in PCV20 and PCV13 groups, with most reported as mild or moderate. The most common local reaction was injection site pain (PCV20, 24.7% to 40.5%; PCV13, 26.8% to 42.0%); irritability was the most common systemic event (PCV20, 54.8% to 68.2%; PCV13, 54.7% to 68.5%). AE frequencies were similar in both groups. No serious AEs were related to study vaccines. Few newly diagnosed chronic medical conditions were reported (2.8% in both groups). PCV20 was safe across multiple countries, in late preterm infants, and when administered with other vaccines. A 4-dose series of PCV20 had a tolerability and safety profile similar to that of PCV13.

Unique Kinetics of the Human Milk Antibody Response to JYNNEOS Vaccine for Prevention of Monkey Pox: A Case Study.

Background: JYNNEOS is a nonreplicating modified vaccinia Ankara vaccine currently licensed to prevent monkeypox infection, and its milk immunogenicity remains unstudied. Objective: Investigate the human milk immunogenicity of the JYNNEOS vaccine in one individual and examine the milk for evidence of vaccine components. Methods: Immunogenicity of milk and plasma samples were tested by Luminex assays against Vaccinia antigens, and vaccine components were tested using PCR and sandwich ELISA. Results: Plasma antibody (Ab) response increased up to 3.7-fold in immunoglobulin G (IgG) titer and 1.4-fold in IgA compared with baseline, confirming vaccine immunogenicity in this participant 2 weeks post dose 2. Specific plasma IgG remained 1.2- to 1.7-fold above baseline 12 weeks post dose 2, while IgA returned to baseline levels. Notably, the milk response exhibited unique kinetics, particularly for IgA. Milk IgA against all three antigens increased 0.9- to 2.2-fold 2 weeks post dose 2, reaching a peak titer increase of 1.1- to 2.7-fold at 12 weeks post dose 2. Secretory (s) Ab levels increased to 1.1- to 2-fold at 2 weeks post dose 2 and reached a peak of 2- to 3.2-fold increase at the 12-week time point. Importantly, IgA and sAb responses in milk exhibited correlation, suggesting most milk IgA was sIgA. Notably, no vaccine components (VACV protein or DNA) were detected in the milk samples. Conclusion: These data suggest that the milk Ab response to this intradermal (ID) VACV-based vaccine is distinct from that observed systemically, indicating a unique mucosal immune response and highlighting its potential to elicit protective long-lasting sIgA. This case report provides strong evidence for inclusion of this vaccine platform in future studies of maternal vaccines aimed to elicit a protective milk Ab response.

Associations between SARS-CoV-2 Infection or COVID-19 Vaccination and Human Milk Composition: A Multi-Omics Approach

BackgroundThe risk of contracting SARS-CoV-2 via human milk-feeding is virtually non-existent. Adverse effects of COVID-19 vaccination for lactating individuals are not different from the general population, and no evidence has been found that their infants exhibit adverse effects. Yet, there remains substantial hesitation among this population globally regarding the safety of these vaccines. ObjectiveHerein we aimed to determine if compositional changes in milk occur following infection or vaccination, including any evidence of vaccine components. Methods and ResultsUsing a subset of milk samples obtained as part of our broad studies examining the effects on milk of SARS-CoV-2 infection and COVID-19 vaccination, an extensive multi-omics approach, we found that compared to unvaccinated individuals SARS-CoV-2 infection was associated with significant compositional differences in 67 proteins, 385 lipids, and 13 metabolites. In contrast, COVID-19 vaccination was not associated with any changes in lipids or metabolites, although it was associated with changes in 13 or fewer proteins. Compositional changes in milk differed by vaccine. Changes following vaccination were greatest after 1-6 hours for the mRNA-based Moderna vaccine (8 changed proteins), 3 days for the mRNA-based Pfizer (4 changed proteins), and adenovirus-based Johnson and Johnson (13 changed proteins) vaccines. Proteins that changed after both natural infection and Johnson and Johnson vaccine were associated mainly with systemic inflammatory responses. In addition, no vaccine components were detected in any milk sample. ConclusionsTogether, our data provide evidence of only minimal changes in milk composition due to COVID-19 vaccination, with much greater changes after natural SARS-CoV-2 infection.

Engineering a cleaved, prefusion-stabilized influenza B virus hemagglutinin by identification and locking of all six pH switches.

Vaccine components based on viral fusion proteins require high stability of the native prefusion conformation for optimal potency and manufacturability. In the case of influenza B virus hemagglutinin (HA), the stem's conformation relies on efficient cleavage. In this study, we identified six pH-sensitive regions distributed across the entire ectodomain where protonated histidines assume either a repulsive or an attractive role. Substitutions in these areas enhanced the protein's expression, quality, and stability in its prefusion trimeric state. Importantly, this stabilization enabled the production of a cleavable HA0, which is further processed into HA1 and HA2 by furin during exocytic pathway passage, thereby facilitating correct folding, increased stability, and screening for additional stabilizing substitutions in the core of the metastable fusion domain. Cryo-EM analysis at neutral and low pH revealed a previously unnoticed pH switch involving the C-terminal residues of the natively cleaved HA1. This switch keeps the fusion peptide in a clamped state at neutral pH, averting premature conformational shift. Our findings shed light on new strategies for possible improvements of recombinant or genetic-based influenza B vaccines.

Mosaic HIV-1 vaccine and SHIV challenge strain V2 loop sequence identity and protection in primates

The failure of human vaccine efficacy trials assessing a mosaic HIV-1 vaccine calls into question the translatability of preclinical SHIV challenge studies that demonstrated high efficacy of this vaccine in primates. Here we present a post hoc immune correlates analysis of HIV-1 Env peptide-binding antibody responses from the NHP13-19 study identifying the V2 loop as the principal correlate of protection in primates. Moreover, we found high V2 loop sequence identity between the Mos1 vaccine component and the SHIV challenge strain, while the vaccine showed considerably lower V2 identity to globally circulating HIV-1 sequences. Thus, the induction of immune responses against the V2 epitope, which had exceptional identity between the vaccine and challenge Env strains, may have contributed to the high protection in primates.

Evaluation of a Quadrivalent Shigella flexneri Serotype 2a, 3a, 6, and Shigella sonnei O-Specific Polysaccharide and IpaB MAPS Vaccine

Background: Shigellosis is the leading cause of diarrheal deaths worldwide and is particularly dangerous in children under 5 years of age in low- and middle-income countries. Additionally, the rise in antibiotic resistance has highlighted the need for an effective Shigella vaccine. Previously, we have used the Multiple Antigen-Presenting System (MAPS) technology to generate monovalent and quadrivalent Salmonella MAPS vaccines that induce functional antibodies against Salmonella components. Methods: In this work, we detail the development of several monovalent vaccines using O-specific polysaccharides (OSPs) from four dominant serotypes, S. flexneri 2a, 3a, and 6, and S. sonnei. We tested several rhizavidin (rhavi) fusion proteins and selected a Shigella-specific protein IpaB. Quadrivalent MAPS were made with Rhavi-IpaB protein and tested in rabbits for immunogenicity. Results: Individual MAPS vaccines generated robust, functional antibody responses against both IpaB and the individual OSP component. Antibodies to IpaB were effective across Shigella serotypes. We also demonstrate that the OSP antibodies generated are specific to each homologous Shigella O type by performing ELISA and bactericidal assays. We combined the components of each MAPS vaccine to formulate a quadrivalent MAPS vaccine which elicited similar antibody and bactericidal responses compared to their monovalent counterparts. Finally, we show that the quadrivalent MAPS immune sera are functional against several clinical isolates of the serotypes used in the vaccine. Conclusions: This quadrivalent MAPS Shigella vaccine is immunogenicity and warrants further study.

Signal peptide exchange alters HIV-1 envelope antigenicity and immunogenicity.

HIV-1 envelope (Env) is the key target for antibodies (Abs) against the virus and thus an important HIV-1 vaccine component. Env is synthesized from a gp160 precursor with a signal peptide (SP) at its N-terminus. This study investigated the influence of the SP on Env antigenicity and immunogenicity. Env proteins from two HIV-1 isolates, AA05 and AC02, were analyzed as gp120 and gp160 in their native wild-type (WT) forms and as chimeras with swapped SPs (AA05-02 and AC02-05). The WT and chimeric Env were assessed for antigenicity and glycosylation using monoclonal antibodies (mAbs) and glycan probes. Immunogenicity was tested in mice using three vaccine types: gp120 protein, gp120 DNA+gp120 protein, and gp120 DNA+gp160 DNA. The recombinant AC02 gp120 protein was antigenically superior to AA05 as indicated by higher reactivity with most mAbs tested. When SPs were swapped, the antigenicity of the chimeric gp120s (AA05-02 and AC02-05) resembled that of the gp120s from which the SPs were derived; AA05-02 was similar to AC02 and vice versa. Glycan probe reactivity followed a similar pattern: AA05-02 and AC02 showed similar affinity to high-mannose specific mAbs and lectins. Interestingly, the antigenicity of gp160s showed an opposite pattern; membrane-bound gp160 expressed with the AA05 SP (AA05 and AC02-05) showed greater mAb binding than gp160 with the AC02 SP (AC02 and AA05-02). Mice immunized with gp120 protein showed that AA05-02 induced stronger cross-reactive binding Ab responses than AA05 WT, and AC02 elicited stronger responses than AC02-05, indicating AC02 SP enhanced gp120 immunogenicity. However, when DNA vaccines were included (gp120 DNA+gp120 protein and gp120 DNA+gp160 DNA), the use of heterologous SPs diminished the immunogenicity of the WT immunogens. Among the three vaccine regimens tested, only gp120 DNA+gp160 DNA immunization elicited low-level Tier 2 neutralizing Abs, with AA05 WT inducing Abs with greater neutralization capabilities than AA05-02. These data demonstrate that the SP can significantly impact the antigenicity and immunogenicity of HIV-1 Env proteins. Hence, while SP swapping is a common practice in constructing Env immunogens, this study highlights the importance of careful consideration of the effects of replacing native SPs on the immunogenicity of Env vaccines.

Identification of three novel linear B-cell epitopes on VP7 of African horse sickness virus using monoclonal antibodies

African horse sickness (AHS) is an acute and subacute infectious disease of equine species caused by the African horse sickness virus (AHSV). The VP7 of AHSV is a group-specific protein conserved in all serotypes and is an excellent candidate for the serological diagnosis and an AHS vaccine component. However, to date, B-cell epitopes on the AHSV VP7 recognized by humoral immune responses remain unclear. This study expressed the recombinant AHSV VP7 soluble in Escherichia coli and purified it for mouse immunization. Four monoclonal antibodies (mAbs) were screened and identified by hybridoma cell fusion, clonal purification, and immunological assays. The B-cell epitopes, recognized by monoclonal antibodies 4B5, 3G10, 3D7, and 4D6, were identified by a series of truncated overlapping peptides expressed as glutathione S-transferase (GST)-fusion proteins. The results revealed that 4B5 recognized the 124VQTGRYAGA132 motif, 3G10 recognized the 140RYYVPQGRT148 motif, while 3D7 and 4D6 recognized the 292QPINPPIFP300 motif. Amino acid sequence alignment indicated that three novel B-cell epitopes were conserved among various AHSV serotypes but unconserved in other orbiviruses, such as the bluetongue and epidemic hemorrhagic disease viruses. This study informs on the antigenic epitopes of AHSV VP7, facilitating future investigations into the serological diagnosis method and epitope-based vaccines against AHSV.

Blood Distribution of SARS-CoV-2 Lipid Nanoparticle mRNA Vaccine in Humans.

Lipid nanoparticle mRNA vaccines are an exciting but emerging technology used in humans. There is limited understanding of the factors that influence their biodistribution and immunogenicity. Antibodies to poly(ethylene glycol) (PEG), which is on the surface of the lipid nanoparticle, are detectable in humans and boosted by human mRNA vaccination. We hypothesized that PEG-specific antibodies could increase the clearance of mRNA vaccines. To test this, we developed methods to quantify both the vaccine mRNA and ionizable lipid in frequent serial blood samples from 19 subjects receiving Moderna SPIKEVAX mRNA booster immunization. Both the vaccine mRNA and ionizable lipid peaked in blood 1-2 days post vaccination (median peak level 0.19 and 3.22 ng mL-1, respectively). The vaccine mRNA was detectable and quantifiable up to 14-15 days postvaccination in 37% of subjects. We measured the proportion of vaccine mRNA that was relatively intact in blood over time and found that the decay kinetics of the intact mRNA and ionizable lipid were identical, suggesting the intact lipid nanoparticle recirculates in blood. However, the decay rates of mRNA and ionizable lipids did not correlate with baseline levels of PEG-specific antibodies. Interestingly, the magnitude of mRNA and ionizable lipid detected in blood did correlate with the boost in the level of PEG antibodies. Furthermore, the ability of a subject's monocytes to phagocytose lipid nanoparticles was inversely related to the rise in PEG antibodies. This suggests that the circulation of mRNA lipid nanoparticles into the blood and their clearance by phagocytes influence the PEG immunogenicity of the mRNA vaccines. Overall, this work defines the pharmacokinetics of lipid nanoparticle mRNA vaccine components in human blood after intramuscular injection and the factors that influence these processes. These insights should be valuable in improving the future safety and efficacy of lipid nanoparticle mRNA vaccines and therapeutics.

COBRA N2 NA vaccines induce protective immune responses against influenza viral infection

ABSTRACT Influenza neuraminidase (NA) is a promising target for a broadly protective vaccine. In this study, the Computationally Optimized Broadly Reactive Antigen (COBRA) methodology was used to develop N2 NA vaccine candidates. The unique wild type (WT) N2 sequences of human and swine influenza strains isolated between 1957 and 2019 were used to design the COBRA N2-A NA vaccine, while the unique WT N2 sequences of human influenza strains isolated between 2000 and 2019 were used to design the COBRA N2-B NA vaccine. Sera collected from COBRA N2 NA vaccinated mice showed more broadly reactive antibody responses against a broad panel of H×N2 influenza virus strains than sera collected from mice vaccinated with WT N2 NA vaccines. Antibodies elicited by COBRA or WT N2 NA antigens cross react with recent human H3N2 influenza viruses from different clades, while the antibodies elicited by A/Switzerland/9715293/2013 hemagglutinin (HA) reacted with viruses from the same clade. Furthermore, mice vaccinated with COBRA N2-B NA vaccine had lower viral lung titers compared to mock vaccinated mice when challenged with human H3N2 influenza viruses. Thus, the COBRA N2 NA vaccines elicit broadly protective murine anti-NA antibodies against multiple strains across subtypes and the viral loads were significantly decreased in the lungs of the mice in the COBRA N2 NA vaccine groups, compared to the mice in the mock vaccinated group, indicating that the COBRA-based N2 subtype NA vaccines have a potential to be a component in a universal influenza vaccine.

Replacing poly(ethylene glycol) with RAFT lipopolymers in mRNA lipid nanoparticle systems for effective gene delivery

Lipid nanoparticles (LNPs) have emerged as promising carriers to efficiently transport mRNA into cells for protein translation, as seen with the mRNA vaccines used against COVID-19. However, they contain a widely used polymer – poly(ethylene glycol) (PEG) – which lacks the functionality to be easily modified (which could effectively control the physicochemical properties of the LNPs such as its charge), and is also known to be immunogenic. Thus, it is desirable to explore alternative polymers which can replace the PEG component in mRNA LNP vaccines and therapeutics, while still maintaining their efficacy. Herein, we employed reversible addition-fragmentation chain transfer (RAFT) polymerisation to synthesise five PEG-lipid alternatives that could stabilise LNPs encapsulating mRNA or pDNA molecules. Importantly, the resultant RAFT lipopolymer LNPs exhibit analogous or higher in vivo gene expression and antigen-specific antibody production compared to traditional PEG-based formulations. Our synthesis strategy which allows the introduction of positive charges along the lipopolymer backbone also significantly improved the in vivo gene expression. This work expands the potential of RAFT polymer-conjugated LNPs as promising mRNA carriers and offers an innovative strategy for the development of PEG-free mRNA vaccines and therapeutics.

Analysis of polyclonal and monoclonal antibody to the influenza virus nucleoprotein in different oligomeric states.

Influenza virus nucleoprotein (NP) is one of the most conserved influenza proteins. Both NP antigen and anti-NP antibodies are used as reagents in influenza diagnostic kits, with applications in both clinical practice, and influenza zoonotic surveillance programs. Despite this, studies on the biochemical basis of NP diagnostic serology and NP epitopes are not as developed as for hemagglutinin (HA), the fast-evolving antigen which has been the critical component of current influenza vaccines. Here, we characterized the NP serology of mice, ferret, and human sera and the immunogenic effects of NP antigen presented as different structural complexes. Furthermore, we show that a classical anti-NP mouse mAb HB65 could detect NP in some commercial influenza vaccines. MAb HB65 bound a linear epitope with nanomolar affinity. Our analysis suggests that linear NP epitopes paired with their corresponding characterized detection antibodies could aid in designing and improving diagnostic technologies for influenza virus.

Prevalence of Influenza B/Yamagata Viruses From Season 2012/2013 to 2021/2022 in Italy as an Indication of a Potential Lineage Extinction.

Influenza B/Yamagata viruses exhibited weak antigenic selection in recent years, reducing their prevalence over time and requiring no update of the vaccine component since 2015. To date, no B/Yamagata viruses have been isolated or sequenced since March 2020. The antibody prevalence against the current B/Yamagata vaccine strain in Italy was investigated: For each influenza season from 2012/2013 to 2021/2022, 100 human serum samples were tested by haemagglutination inhibition (HAI) assay against the vaccine strain B/Phuket/3073/2013. In addition, the sequences of 156 B/Yamagata strains isolated during the influenza surveillance activities were selected for analysis of the haemagglutinin genome segment. About 61.9% of the human samples showed HAI antibodies, and 21.7% had protective antibody levels. The prevalence of antibodies at protective levels in the seasons between the isolation of the strain and its inclusion in the vaccine was between 11% and 25%, with no significant changes observed in subsequent years. A significant increase was observed in the 2020/2021 season, in line with the increase in influenza vaccine uptake during the pandemic. Sequence analysis showed that from 2014/2015 season onward, all B/Yamagata strains circulating in Italy were closely related to the B/Phuket/2013 vaccine strain, showing only limited amino acid variation. A consistent prevalence of antibodies to the current B/Yamagata vaccine strain in the general population was observed. The prolonged use of a well-matched influenza vaccine and a low antigenic diversity of B/Yamagata viruses may have facilitated a strong reduction in B/Yamagata circulation, potentially contributing to the disappearance of this lineage.

Vaccines and allergy: Back to the right places.

Hypersensitivity reactions represent one of the most common causes of hesitancy for adherence to national vaccination programs. The majority of hypersensitivity reactions after vaccination are mild, and anaphylaxis is reported to be rare, although it remains challenging to estimate the frequency attributed to each single vaccine, either because of the lower number of administered doses of less common vaccines, or the administration of simultaneous vaccine in most of the vaccination programs. Although literature remains scattered, international consensus guides clinicians in identifying patients who might need the administration of vaccines in protected environments due to demonstrated hypersensitivity to vaccine components or adjuvants. Here we provide the current guidance on hypersensitivity reactions to vaccines and on vaccination of children with allergy disorders.

Antibodies against the strangles vaccine component CCE inhibit both alpha‐2‐macroglobulin and albumin binding

Antibodies against the strangles vaccine component <scp>CCE</scp> inhibit both alpha‐2‐macroglobulin and albumin binding