Immune Responses of Mice Immunized with HBsAg Formulated in Naloxone/Alum Mixture: Comparison to Fendrix Vaccine

Abstract

Background: Hepatitis B virus (HBV) can cause cirrhosis of the liver and hepatocellular carcinoma. Due to the lack of sufficient immune response in whole population, several studies have been conducted to improve the efficacy of alum- based HBV vaccine. Here, naloxone/alum mixture as adjuvant was used for the hepatitis B surface antigen HBsAg vaccine and immune parameters evaluated in immunized mice. Objectives: The present study aimed at investigating the effect of naloxone/alum mixture for the HBsAg vaccine and comparing to Fendrix vaccine. Methods: Female Balb/c mice were vaccinated at day 0, 14, and 28 with alum- based vaccine or naloxone/alum mixture vaccine in different doses. Naloxone/alum vaccine groups received a dose of 3, 6, or 10 mg/kg of naloxone (NLX) in the vaccine formulation. One group received routine HBsAg alum vaccine and another group received Fendrix vaccine. Some groups received naloxone plus HBsAg without alum and a group received HBsAg without adjuvant. Phosphate buffered saline (PBS), naloxone, and alum were also injected into the control groups separately. Finally, the naloxone/alum formulated vaccine was compared with the Fendrix and routine alum- based vaccine with respect to the levels of total anti-HBS antibody, IFN-γ, IL-4, IgG1, IgG2a, and the level of lymphocyte proliferation. Results: The level of total anti-HBS antibody in naloxone formulated vaccine was comparable with Fendrix. Meanwhile, IFN-γ/IL-4 ratio level was significantly higher in naloxone formulated vaccine groups versus mere vaccine group. IgG2a was also higher in the naloxone formulated vaccine groups. Conclusions: Based on the data presented in the present study, it was found that naloxone/alum mixture has the ability to shift the immune response towards Th1 pattern and potentially increase immunity against infections.