Improved Aluminum Adjuvants Eliciting Stronger Immune Response When Mixed with Hepatitis B Virus Surface Antigens

Application of plant-derived products as adjuvants for immune activation and vaccine development

Vaccines are one of the most important means to prevent and control the epidemic of infectious diseases. Commercial vaccines not only include corresponding antigens, but also need vaccine adjuvants. Immune adjuvants play an increasingly important role in the research, development and manufacture of vaccines. Adjuvants combined with antigens can improve the stability, safety and immune efficiency of vaccines. Some substances that can enhance the immune response have been found in nature(mainly plants) and used as adjuvants in vaccines to improve the immune effect of vaccines. These plant-derived immune adjuvants often have the advantages of low toxicity, high stability, low price, etc., providing more possibilities for vaccine development. We summarized and analyzed the advantages, application research, particulate delivery systems, existing problems and future research focus of botanical adjuvant. It is hoped to provide new ideas for the research and development of immune adjuvants in the future.

Overview of Hepatitis B Vaccine Non-Response and Associated B Cell Amnesia: A Scoping Review

BACKGROUND

The advent of the hepatitis B vaccine has achieved tremendous success in eradicating and reducing the burden of hepatitis B infection, which is the main culprit for hepatocellular carcinoma-one of the most fatal malignancies globally. Response to the vaccine is achieved in about 90-95% of healthy individuals and up to only 50% in immunocompromised patients. This review aimed to provide an overview of hepatitis B vaccine non-response, the mechanisms involved, B cell amnesia, and strategies to overcome it.

METHODS

Databases, including Google Scholar, PubMed, Scopus, Cochrane, and ClinicalTrials.org, were used to search and retrieve articles using keywords on hepatitis B vaccine non-response and B cell amnesia. The PRISMA guideline was followed in identifying studies, screening, selection, and reporting of findings.

RESULTS

A total of 133 studies on hepatitis B vaccine non-response, mechanisms, and prevention/management strategies were included in the review after screening and final selection. Factors responsible for hepatitis B vaccine non-response were found to include genetic, immunological factors, and B cell amnesia in healthy individuals. The genetic factors were sex, HLA haplotypes, and genetic polymorphisms in immune response markers (cytokines). Non-response was common in conditions of immunodeficiency, such as renal failure, haemodialysis, celiac disease, inflammatory bowel disease, hepatitis C co-infection, and latent hepatitis B infection. Others included diabetes mellitus and HIV infection. The mechanisms involved were impaired immune response by suppression of response (T helper cells) or induced suppression of response (through regulatory B and T cells).

DISCUSSION

A comprehensive and careful understanding of the patient factors and the nature of the vaccine contributes to developing effective preventive measures. These include revaccination or booster dose, vaccine administration through the intradermal route, and the use of adjuvants in the vaccine.

Nanomedicine approaches against SARS-CoV-2 and variants

The world is grappling with the ongoing crisis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), a global pandemic that continues to have a detrimental impact on public health and economies worldwide. The virus's relentless mutation has led to more transmissible, immune-evasive strains, thereby escalating the incidence of reinfection. This underscores the urgent need for highly effective and safe countermeasures against SARS-CoV-2 and its evolving variants. In the current context, nanomedicine presents an innovative and promising alternative to mitigate the impacts of this pandemic wave. It does so by harnessing the structural and functional properties at a nanoscale in a straightforward and adaptable manner. This review emphasizes the most recent progress in the development of nanovaccines, nanodecoys, and nanodisinfectants to tackle SARS-CoV-2 and its variants. Notably, the insights gained and strategies implemented in managing the ongoing pandemic may also offer invaluable guidance for the development of potent nanomedicines to combat future pandemics.

Formalin and ferric chloride inactivated Pasteurella multocida type a adjuvanted with bacterial DNA and alum as a new vaccine candidate in sheep pasteurellosis

The aim of the present study was to investigate humoral and cellular immune responses in sheep inoculated with inactivated P. multocida antigen with alum and bacterial DNA adjuvant by identifying IgG and cytokines from serum and cell culture. Sheep were immunized with iron and formalin-inactivated antigens at an interval of 2 weeks. These immunogens were mixed with alum adjuvant and P. multocida type A DNA (AbDNA). After injection and blood sampling, the serum antibody titer and cellular immune responses (IL-4, IFN-γ, and TNF-α) on serum samples and lymphocyte cell were tested by ELISA. The ELISA results showed a higher antibody titer in the bDNA adjuvant group compared to the alum adjuvant group and the control group. In general, the level of IgG in the serum of immunized animals was significantly increased compared to the control group. The peak antibody titer (1.794) was observed on the 28th day of injection in the IIV-AbDNA group. After immunization, inactivation with iron and bDNA adjuvant increased cytokine production compared to other experimental and control groups. High levels of lymphocyte and serum titers of IL-4, IFN-γ, and TNF-α were also obtained in the IIV-AbDNA group. The findings showed that killed P. multocida type A antigens formulated with bacterial DNA as an adjuvant are candidates for new immunogens against P. multocida infections in sheep. The inactivation of bacteria with iron also enhanced proper immune responses.

Quality attributes of CTVad1, a nanoemulsified adjuvant for phase I clinical trial of SpiN COVID-19 vaccine

Aim: To develop, characterize and evaluate an oil/water nanoemulsion with squalene (CTVad1) to be approved as an adjuvant for the SpiN COVID-19 vaccine clinical trials. Materials & methods: Critical process parameters (CPPs) of CTVad1 were standardized to meet the critical quality attributes (CQAs) of an adjuvant for human use. CTVad1 and the SpiN-CTVad1 vaccine were submitted to physicochemical, stability, in vitro and in vivo studies. Results & conclusion: All CQAs were met in the CTVad1 production process. SpiN- CTVad1 met CQAs and induced high levels of antibodies and specific cellular responses in in vivo studies. These results represented a critical step in the process developed to meet regulatory requirements for the SpiN COVID-19 vaccine clinical trial.

Enhancement of Immune Response of Bioconjugate Nanovaccine by Loading of CpG through Click Chemistry

CpG is a widely used adjuvant that enhances the cellular immune response by entering antigen-presenting cells and binding with receptors. The traditional physical mixing of the antigen and CpG adjuvant results in a low adjuvant utilization rate. Considering the efficient delivery capacity of nanovaccines, we developed an attractive strategy to covalently load CpG onto the nanovaccine, which realized the co-delivery of both CpG and the antigen. Briefly, the azide-modified CpG was conjugated to a bioconjugate nanovaccine (NP-OPS) against Shigella flexneri through a simple two-step reaction. After characterization of the novel vaccine (NP-OPS-CpG), a series of in vitro and in vivo experiments were performed, including in vivo imaging, lymph node sectioning, and dendritic cell stimulation, and the results showed that more CpG reached the lymph nodes after covalent coupling. Subsequent flow cytometry analysis of lymph nodes from immunized mice showed that the cellular immune response was greatly promoted by the nanovaccine coupled with CpG. Moreover, by analyzing the antibody subtypes of immunized mice, NP-OPS-CpG was found to further promote a Th1-biased immune response. Thus, we developed an attractive method to load CpG on a nanovaccine that is simple, convenient, and is especially suitable for immune enhancement of vaccines against intracellular bacteria.

Improvement influenza vaccine immune responses with traditional Chinese medicine and its active ingredients

The current influenza vaccines are unable to provide effective protection in many cases, like influenza viruses strain antigenic drift or shift, and the influenza continues to cause significant annual morbidity and mortality. Improving the immune response to influenza vaccination is an unmet need. Traditional Chinese medicine (TCM) and its active ingredients are commonly known to have immunomodulatory properties. We therefore compared influenza vaccination alone or formulated with Astragali Radix (Huangqi in Chinese), and several representative ingredients of TCM, including lentinan (polysaccharide), panax notoginseng saponins (saponin), breviscapine (flavone), andrographolide (terpenoid), and a Chinese herbal compound (kangai) for their potential to enhance immune responses to influenza vaccine in mice. We found that all these TCM-adjuvants were able to increase hemagglutination inhibition (HAI) antibody titers, splenocyte proliferation, splenic T cell differentiation, bone marrow dendritic cell maturity, and both Th1 and Th2 cytokine secretion of influenza vaccine to varying degrees, and that had the characteristics of no excessive inflammatory responses and bidirectional regulation simultaneously. Taken together, our findings show that Astragali Radix exerts a more comprehensive effect on vaccine immunity, on both innate and adaptive immunity. The effects of lentinan and andrographolide on adaptive immunity were more significant, while the effects of breviscapine on innate immunity were stronger, and the other two TCM adjuvants were weaker. As the first report of a comprehensive evaluation of TCM adjuvants in influenza vaccines, the results suggest that TCM and their active ingredients are good candidates for enhancing the immune response of influenza vaccines, and that suitable TCMs can be selected based on the adjuvant requirements of different vaccines.