ObjectiveEuCorVac-19 (ECV-19), an adjuvanted liposome-displayed receptor binding domain (RBD) COVID-19 vaccine, previously reported interim Phase 2 trial results showing induction of neutralizing antibodies 3 weeks after prime-boost immunization. The objective of this study was to determine the longer-term antibody response of the vaccine. MethodsTo assess immunogenicity 6 and 12 months after vaccination, participants in the Phase 2 trial (NCT04783311) were excluded if they: 1) withdrew, 2) reported COVID-19 infection or additional vaccination, or 3) exhibited increasing Spike (S) antibodies (representing possible non-reported infection). Following exclusions, of the 197 initial subjects, anti-S IgG antibodies and neutralizing antibodies were further assessed in 124 subjects at the 6-month timepoint, and 36 subjects at the 12-month timepoint. ResultsMedian anti-S antibody half-life was 52 days (interquartile range [IQR]:42-70), in the “early” period from 3 weeks to 6 months, and 130 days (IQR:97-169) in the “late” period from 6 to 12 months. There was a negative correlation between initial antibody titer and half-life. Anti-S and neutralizing antibody responses were correlated. Neutralizing antibody responses showed longer half-lives; the early period had a median half-life of 120 days (IQR:81-207), and the late period had a median half-life of 214 days (IQR:140-550). ConclusionThese data establish antibody durability of ECV-19, using a framework to analyze COVID-19 vaccine-induced antibodies during periods of high infection.

There is a need for next-generation cholera vaccines that provide high-level and durable protection in young children in cholera-endemic areas. A cholera conjugate vaccine (CCV) is in development to address this need. This vaccine contains the O-specific polysaccharide (OSP) of Vibrio cholerae O1 conjugated via squaric acid chemistry to a recombinant fragment of the tetanus toxin heavy chain (OSP:rTTHc). This vaccine has been shown previously to be immunogenic and protective in mice and found to be safe in a recent preclinical toxicological analysis in rabbits. We took advantage of excess serum samples collected as part of the toxicological study and assessed the immunogenicity of CCV OSP:rTTHc in rabbits. We found that vaccination with CCV induced OSP-, lipopolysaccharide (LPS)-, and rTTHc-specific immune responses in rabbits, that immune responses were functional as assessed by vibriocidal activity, and that immune responses were protective against death in an established virulent challenge assay. CCV OSP:rTTHc immunogenicity in two animal model systems (mice and rabbits) is encouraging and supports further development of this vaccine for evaluation in humans.

The use of global standards, and the placement of barcodes and data matrix codes on vaccine labels and other levels of packaging are crucial elements for the traceability of finished vaccine products. Vaccine manufacturers are committed to improving health through their products, as vaccine production offers opportunities that can be leveraged to benefit immunization systems. In 2019 the Developing Countries Vaccine Manufacturers Network (DCVMN) created the Supply Chain Initiative aimed at prioritize and explore traceability opportunities; concomitantly procurement agencies announced traceability requirements for vaccine global supply. Vaccine traceability brings benefits including supply chain reliability and safety through enhanced product movement visibility, and a reduction of falsified and expired vaccines circulating in the supply chain. DCVMN has coordinated the development and implementation of global traceability standards, at both primary and secondary vaccine packaging levels, to encourage and enable sharing these experiences. Six pilot studies in four different countries showed successful implementation, and constituted part of larger vaccine traceability work within the respective organizations. The main findings from these pilot studies indicated that stepwise approaches to the adoption of traceability standards allowed vaccine manufacturers to learn by doing, initially with lower risk, and to spread their investments over time. Because the value of traceability is in its scale of adoption and the use of the data, it remains important for all stakeholders to engage in and prioritize the journey of vaccine traceability, but also to suitably manage the financial risks. The DCVMN Supply Chain Initiative has demonstrated that its members are committed to driving supply system changes that benefit immunization, while recognizing that supply chain traceability is part of a larger healthcare ecosystem and should be adopted by countries and immunization programmes as well.

The current production of the Japanese encephalitis virus (JEV) vaccine is based on animal cells, where various risk factors for human health should be resolved. This study used a transient expression system to express the chimeric protein composed of antigenic epitopes from the JEV envelope (E) protein in Nicotiana benthamiana. JEV multi-epitope peptide (MEP) sequences fused with FLAG-tag or 6× His-tag at the C- or N-terminus for the purification were introduced into plant expression vectors and used for transient expression. Among the constructs, vector pSK480, which expresses MEP fused with a FLAG-tag at the C-terminus, showed the highest level of expression and yield in purification. Optimization of transient expression procedures further improved the target protein yield. The purified MEP protein was applied to an ICR mouse and successfully induced an antibody against JEV, which demonstrates the potential of the plant-produced JEV MEP as an alternative vaccine candidate.

Commensal bacteria are critically involved in the establishment of tolerance against inflammatory challenges, the molecular mechanisms of which are just being uncovered. All kingdoms of life produce aminoacyl-tRNA synthetases (ARSs). Thus far, the non-translational roles of ARSs have largely been reported in eukaryotes. Here, we report that the threonyl-tRNA synthetase (AmTARS) of the gut-associated bacterium Akkermansia muciniphila is secreted and functions to monitor and modulate immune homeostasis. Secreted AmTARS triggers M2 macrophage polarization and orchestrates the production of anti-inflammatory IL-10 via its unique, evolutionary-acquired regions, which mediates specific interactions with TLR2. This interaction activates the MAPK and PI3K/AKT signaling pathways, which converge on CREB, leading to an efficient production of IL-10 and suppression of the central inflammatory mediator NF-κB. AmTARS restores IL-10-positive macrophages, increases IL-10 levels in the serum, and attenuates the pathological effects in colitis mice. Thus, commensal tRNA synthetases can act as intrinsic mediators that maintain homeostasis.

Abstract Among many candidates from the recent diverging research to develop a multivalent platform, IgM has shown potential as a pharmaceutical because of its avidity coming from natural multimeric target binding ability. IgM has a great advantage of naturally forming multimers, however, there are some unfulfilled needs to become a good pharmaceutical platform, such as limited biological activity, short half-life, safety concerns, and difficult purification steps compared to IgG. Here, we developed an antibody platform, ePENDY, by engineering IgM to improve efficacy, safety, and convenience of manufacturing process. ePENDY has a self-assembling decavalent pentameric structure and it is an improved IgM with maximized biological activity as therapeutics by using flexible linkers. In addition, ePENDY was engineered one of the effector functions of antibodies, ADCC, was greatly increased compared to IgG as well as IgM which does not have this function. More importantly, the presence or absence of effector functions can be controlled depending on the MoA (Mode of action) of the target. Serum half-life of ePENDY was significantly increased compared to natural IgM, and ePENDY showed similar PK profiles as the IgG Fc-based molecules through FcRn recycling. Unlike natural IgM, ePENDY does not bind to any IgM receptors, such as pIgR, FcμR, and Fcα/μR, thereby eliminating possible side effects. In addition, it has been confirmed that ePENDY showed a comparable expression level to that of IgG, and since the purification process can also be set up in a process like IgG, thus production of ePENDY can be facilitated. Based on these results, we are researching ePENDY which are applying various therapeutic molecules, such as antibodies, protein ligand-based active molecules and therapeutic cancer vaccines. We expect that our versatile applicable platform, safe and long acting ePENDY, can be a superior tool for the various therapeutic targets. Citation Format: Sungmuk Kang, Hyeonju Kang, Jihye Koo, Yoojin Kim, Suho Park, Inyoung Lee, Jiye Yi, Hong Jai Lee, Yonghyun Cho, Hyunju Hwang, Kyunggi Hyun, Chungmin Lee, Gyongsik Ha. Next generation IgM antibody based multimeric platform: ePENDY (engineered pentamer body) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1532.

The gram-negative bacterium Shigella is an enteric pathogen responsible for significant morbidity and mortality due primarily to severe diarrhea and dysentery, mainly among children younger than five years of age living in low- and middle-income countries (LMICs). Long considered a priority target for vaccine development, recent scientific advances have led to a number of promising Shigella vaccine candidates now entering advanced stages of clinical testing. Yet, there is no guarantee that even a highly efficacious Shigella vaccine will be recommended, prioritized, purchased, and widely adopted-especially if it requires additional doses in the immunization schedule and/or visits within the immunization program. This uncertainty is due to a variety of factors, including continuing declines in Shigella-specific and overall diarrheal disease mortality rates, the increasing complexity and cost of infant immunization programs in LMICs, and the recent availability of other high-priority vaccines. Since combining a Shigella vaccine with an existing infant vaccine would conceivably increase its attractiveness, there is a need to systematically consider the challenges determining the public health value, clinical development, manufacturing, licensure, policy recommendations, and financing for a Shigella-containing combination vaccine. The international non-governmental health organization PATH convened an independent panel of 34 subject matter experts across academic, industry, philanthropic, and global health sectors to discuss hypothetical combinations of a notional parenteral Shigella vaccine with three existing vaccines in order to begin exploring the challenges associated with their development. The resulting insights and recommendations from this meeting contribute to PATH's broader effort to evaluate the public health value of potential Shigella vaccines. They may also help guide future combination vaccine development efforts more broadly.

The typhoid conjugate vaccine (TCV) ensures a long-lasting protective immune response, requires fewer doses and is fit for children under 2years of age. From Phase I study, EuTCV displayed considerable immunogenicity and reliable safety, thus endorsing further examination in Phase II/III trials. Therefore, a clinical Phase II/III study (NCT04830371) was conducted to evaluate its efficacy in healthy Filipino participants aged 6months to 45years through administration of the test vaccine (Arm A, B, and C) or comparator vaccine Typbar-TCV® (Arm D). Sera samples were collected pre-vaccination (Visit 1) and post-vaccination (Visit 4, Day 28) to assess the immunogenicity of EuTCV and Typbar-TCV®. During the study, participants were regularly monitored through scheduled visits to the clinic to report any adverse events associated with the vaccine. For vaccine safety, the proportion of solicited and unsolicited Treatment-Emergent Adverse Events was all comparable between EuTCV and Typbar-TCV® groups. A single dose of EuTCV produced seroconversion in 99.4% of treated participants, with seroconversion rates non-inferior to that of Typbar-TCV®. Batch-to-batch consistency was concluded based on the 90% Confidence Interval of the geometric mean ratio (EuTCV Arm A, B, and C) at Week 4, lying within the equivalence margin of 0.5 to 2.0 for all batches. Results from this Phase II/III clinical trial of EuTCV in healthy volunteers show comparable safety and considerable immunogenicity, compared to Typbar-TCV®, meeting the objectives of this pivotal study. ClinicalTrials.gov registration number: NCT04830371.

AbstractVaccine packaging innovations have a potential impact on the supply chain, as well as acceptability and uptake by users. To better understand recent developments in packaging innovations, we assessed the benefits and challenges of compact pre‐filled auto‐disable devices (CPADs), polymer‐based primary containers (or vials), and dual‐chamber delivery devices. These packaging innovations have clear public health benefits related to ease of use, improved safety, supply logistics, and uptake enabling new vaccination opportunities. In addition, there seems to be high acceptability from users at country‐level. However, uncertain costs including the impact on distribution and cold chain storage have hampered demand and consequently commercialization. For innovations to reach those who can benefit most, global stakeholders should place greater attention on new packaging technologies and assess the trade‐offs between safety, coverage, uptake, ease of administration, wastage and costs.