No abstract

Hepatitis B viral (HBV) infections represent major public health problem and are an occupational hazard for healthcare workers. Current alum-adjuvanted HBV vaccine is the most effective measure to prevent HBV infection. However, the vaccine has some limitations including poor response in some vaccinee and being a frost-sensitive suspension. The goal of our study was to use an alternative natural adjuvant system strongly immunogenic allowing for a reduction in dose and cost. We tested HBV surface antigen (HBsAg) adjuvanted with chitosan (Ch) and sodium alginate (S), both natural adjuvants, either alone or combined with alum in mouse model. Mice groups were immunized subcutaneously with HBsAg adjuvanted with Ch or S, or triple adjuvant formula with alum (Al), Ch, and S, or double formulations with AlCh or AlS. These were compared to control groups immunized with current vaccine formula or unadjuvanted HBsAg. We evaluated the rate of seroconversion, serum HBsAg antibody, IL-4, and IFN-γ levels. The results showed that the solution formula with Ch or S exhibited comparable immunogenic responses to Al-adjuvanted suspension. The AlChS gave significantly higher immunogenic response compared to controls. Collectively, our results indicated that Ch and S are effective HBV adjuvants offering natural alternatives, potentially reducing dose.

MMR vaccine is a common vaccine that contains oncolytic viruses (Measles, Mumps, and Rubella) and could be used as a potential anti-cancer treatment. In this study, we assessed the anti-tumor activity of the MMR vaccine against Ehrlich ascites carcinoma (EAC) solid tumor induced in mice. The in vitro assay showed that vaccine IC50 in EAC was approximately 200 CCID50. The vaccine was intratumorally administrated twice weekly in EAC-bearing mice. The antitumor response of the vaccine was measured by tumor growth, survival rate, histopathologic examination, flow cytometry analysis, and body biochemical parameters. The MMR vaccine demonstrated a substantial reduction of tumor growth and prolongation of life span as well. The proliferation marker was significantly lower in the vaccine-treated group. Moreover, the apoptosis key parameter Casp-3 was also higher in the vaccine-treated group. The vaccine somewhat restored the deterioration of the biochemical parameters (LDH, GOT, GPT, MDA, NO, and PON-1) in the tumor-bearing mice. Finally, this study indicated the potential antitumor effect of MMR vaccine via anti‑proliferative, apoptotic activities, and modulating the antioxidant parameters. This study opens a new field of inquiry for future research on the vaccine’s anti-cancer properties.

Chitosan and alginate salts are natural biopolymers that have gained recent attention in the biomedical sectors. Their properties allow them to become potential candidates as safe, cheap, and effective vaccine adjuvants. The present study aimed to enhance the immunogenic response of a current injectable killed cholera vaccine (KCV) using chitosan and alginate salt as natural adjuvants against alum. We tested KCV adjuvanted with alum, chitosan, and sodium alginate in mice. Mice were immunized intraperitoneally with KCV adjuvanted with alum, chitosan, or alginate salt and compared with a control unadjuvanted immunized group. Humoral, cellular, and functional immune responses were evaluated in all groups. The addition of adjuvants, particularly natural adjuvants, to KCV significantly improved the immune response as demonstrated by specific antibody increase, strong proliferation effects, and high protection rate against different challenge doses of cholera strains. Our findings demonstrate that chitosan and alginate salt are superior adjuvants for boosting the KCV immune response and highlights the requirement for further vaccine development.