A New Nano Adjuvant of PF3 Used for an Enhanced Hepatitis B Vaccine

Dopamine Inhibits the Expression of Hepatitis B Virus Surface and e Antigens by Activating the JAK/STAT Pathway and Upregulating Interferon-stimulated Gene 15 Expression

Background and Aims

Hepatitis B virus (HBV) infection is a major risk factor for cirrhosis and liver cancer, and its treatment continues to be difficult. We previously demonstrated that a dopamine analog inhibited the packaging of pregenomic RNA into capsids. The present study aimed to determine the effect of dopamine on the expressions of hepatitis B virus surface and e antigens (HBsAg and HBeAg, respectively) and to elucidate the underlying mechanism.

Methods

We used dopamine-treated HBV-infected HepG2.2.15 and NTCP-G2 cells to monitor HBsAg and HBeAg expression levels. We analyzed interferon-stimulated gene 15 (ISG15) expression in dopamine-treated cells. We knocked down ISG15 and then monitored HBsAg and HBeAg expression levels. We analyzed the expression of Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway factors in dopamine-treated cells. We used dopamine hydrochloride-treated adeno-associated virus/HBV-infected mouse model to evaluate HBV DNA, HBsAg, and HBeAg expression. HBV virus was collected from HepAD38.7 cell culture medium.

Results

Dopamine inhibited HBsAg and HBeAg expression and upregulated ISG15 expression in HepG2.2.15 and HepG2-NTCP cell lines. ISG15 knockdown increased HBsAg and HBeAg expression in HepG2.2.15 cells. Dopamine-treated cells activated the JAK/STAT pathway, which upregulated ISG15 expression. In the adeno-associated virus-HBV murine infection model, dopamine downregulated HBsAg and HBeAg expression and activated the JAK-STAT/ISG15 axis.

Conclusions

Dopamine inhibits the expression of HBsAg and HBeAg by activating the JAK/STAT pathway and upregulating ISG15 expression.

Microparticulated Polygonatum sibiricum polysaccharide shows potent vaccine adjuvant effect

Adjuvants are necessary for protein vaccines and have been used for nearly 100 years. However, developing safe and effective adjuvants is still urgently needed. Polysaccharides isolated from traditional Chinese medicine are considered novel vaccine adjuvant sources. This study aimed to investigate the adjuvant activity and immune-enhancing mechanisms of the microparticulated Polygonatum sibiricum polysaccharide (MP-PSP) modified by calcium carbonate. PSP demonstrated adjuvant activity, and MP-PSP further showed a higher humoral response compared to PSP. Subsequently, MP-PSP was elucidated to improving the immunity by slowing the rate of antigen release and activating dendritic cells along with interleukin-6 secretion through toll-like receptor 4 signaling, followed by T follicular helper cell and B cell interactions. Moreover, MP-PSP had a good safety profile in vaccinated mice. Thus, MP-PSP may be a promising vaccine adjuvant and warrants further investigation.

Enhancing TB Vaccine Efficacy: Current Progress on Vaccines, Adjuvants and Immunization Strategies

Tuberculosis (TB) remains a global infectious disease primarily transmitted via respiratory tract infection. Presently, vaccination stands as the primary method for TB prevention, predominantly reliant on the Bacillus Calmette-Guérin (BCG) vaccine. Although it is effective in preventing disseminated diseases in children, its impact on adults is limited. To broaden vaccine protection, efforts are underway to accelerate the development of new TB vaccines. However, challenges arise due to the limited immunogenicity and safety of these vaccines, necessitating adjuvants to bolster their ability to elicit a robust immune response for improved and safer immunization. These adjuvants function by augmenting cellular and humoral immunity against M. tuberculosis antigens via different delivery systems, ultimately enhancing vaccine efficacy. Therefore, this paper reviews and summarizes the current research progress on M. tuberculosis vaccines and their associated adjuvants, aiming to provide a valuable reference for the development of novel TB vaccines and the screening of adjuvants.

HBV Vaccines: Advances and Development

Hepatitis B virus (HBV) infection is a global public health problem that is closely related to liver cirrhosis and hepatocellular carcinoma (HCC). The prevalence of acute and chronic HBV infection, liver cirrhosis, and HCC has significantly decreased as a result of the introduction of universal HBV vaccination programs. The first hepatitis B vaccine approved was developed by purifying the hepatitis B surface antigen (HBsAg) from the plasma of asymptomatic HBsAg carriers. Subsequently, recombinant DNA technology led to the development of the recombinant hepatitis B vaccine. Although there are already several licensed vaccines available for HBV infection, continuous research is essential to develop even more effective vaccines. Prophylactic hepatitis B vaccination has been important in the prevention of hepatitis B because it has effectively produced protective immunity against hepatitis B viral infection. Prophylactic vaccines only need to provoke neutralizing antibodies directed against the HBV envelop proteins, whereas therapeutic vaccines are most likely needed to induce a comprehensive T cell response and thus, should include other HBV antigens, such as HBV core and polymerase. The existing vaccines have proven to be highly effective in preventing HBV infection, but ongoing research aims to improve their efficacy, duration of protection, and accessibility. The routine administration of the HBV vaccine is safe and well-tolerated worldwide. The purpose of this type of immunization is to trigger an immunological response in the host, which will halt HBV replication. The clinical efficacy and safety of the HBV vaccine are affected by a number of immunological and clinical factors. However, this success is now in jeopardy due to the breakthrough infections caused by HBV variants with mutations in the S gene, high viral loads, and virus-induced immunosuppression. In this review, we describe various types of available HBV vaccines, along with the recent progress in the ongoing battle to develop new vaccines against HBV.

Liver Cell Type-Specific Targeting by Nanoformulations for Therapeutic Applications

Hepatocytes exert pivotal roles in metabolism, protein synthesis and detoxification. Non-parenchymal liver cells (NPCs), largely comprising macrophages, dendritic cells, hepatic stellate cells and liver sinusoidal cells (LSECs), serve to induce immunological tolerance. Therefore, the liver is an important target for therapeutic approaches, in case of both (inflammatory) metabolic diseases and immunological disorders. This review aims to summarize current preclinical nanodrug-based approaches for the treatment of liver disorders. So far, nano-vaccines that aim to induce hepatitis virus-specific immune responses and nanoformulated adjuvants to overcome the default tolerogenic state of liver NPCs for the treatment of chronic hepatitis have been tested. Moreover, liver cancer may be treated using nanodrugs which specifically target and kill tumor cells. Alternatively, nanodrugs may target and reprogram or deplete immunosuppressive cells of the tumor microenvironment, such as tumor-associated macrophages. Here, combination therapies have been demonstrated to yield synergistic effects. In the case of autoimmune hepatitis and other inflammatory liver diseases, anti-inflammatory agents can be encapsulated into nanoparticles to dampen inflammatory processes specifically in the liver. Finally, the tolerance-promoting activity especially of LSECs has been exploited to induce antigen-specific tolerance for the treatment of allergic and autoimmune diseases.

Adjuvanted quaternized chitosan composite aluminum nanoparticles-based vaccine formulation promotes immune responses in chickens

Aluminum adjuvant is a typical adjuvant that can promote humoral immune response, but it lacks the ability to effectively induce cellular immune response. The water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan nanoparticles (N-2-HACC NPs) can enhance humoral and cellular immune responses of vaccines. To enable aluminum adjuvant to induce cellular immunity, the composite nano adjuvant N-2-HACC-Al NPs were synthesized by the N-2-HACC and aluminum sulfate (Al₂(SO₄)₃). The particle size and zeta potential of the N-2-HACC-Al NPs were 300.70 ± 24.90 nm and 32.28 ± 0.52 mV, respectively. The N-2-HACC-Al NPs have good thermal stability and biodegradability and lower cytotoxicity. In addition, to investigate the immunogenicity of the composite nano adjuvant, the combined inactivated vaccine against Newcastle disease (ND) and H9N2 avian influenza (AI) was prepared with the N-2-HACC-Al NPs as a vaccine adjuvant. The immune effect of the vaccine (N-2-HACC-Al/NDV-AIV) was evaluated by chicken in vivo immunization. The vaccine induced higher levels of serum IgG, IL-4, and IFN-γ than those of the commercial combined inactivated vaccine against ND and H9N2 AI. The levels of IFN-γ were more than twice those of the commercial vaccine at 7 days post the immunization. The N-2-HACC-Al NPs could be used as an efficient nano adjuvant to enhance the effectiveness of vaccine and have immense application potential.