Journal of Liver

Humoral and cellular immune responses in mice against modified Hepatitis B plasmid DNA vaccine

World Congress on Hepatitis

July 20-22, 2015 Orlando, Florida, USA

Mounir M Salem-Bekhit1, 2, Mahmoud M Tawfick1 and Mohsn A Bayoumi2

Posters-Accepted Abstracts: J Liver

Abstract:

Background: Hepatitis B virus (HBV) infection is one of the most widespread viral infections of humans.The recombinant hepatitis B surface antigen (HBsAg), the most commonly used vaccine against HBV, has been used for many years but with limiting efficacy. Objective: This study aimed to evaluate the immunogenicity and type of immune responses of a quality controlled modified gWizHBs plasmid encoding the HbsAg following intramuscular injection of the plasmid in mice. Methods: The characterized plasmid DNA was used in immunization of Balb/c mice by intramuscular route. Three groups of mice were injected with three different concentrations of the modified plasmid. The humoral immune response was monitored by ELISA while the cellular immune response was investigated through analysis of the spleen cytokine profile [TNF?, IFN ?, and IL2] as well as the CD69 expression level in CD4 and CD8 positive cells. Results: In general the percent of activated CD4 cells showing intracellular cytokines was higher than the CD8 positive population of cells. These findings indicate that the vaccine induced both a humoral and cellular immunity. The serum antibody showed first an IgM response at the 2nd and 3rd weeks followed by IgG response that appeared at week 3 and lasted for 6 weeks. This serum antibody level varied with the concentration of plasmid DNA injected and the highest level was obtained when the animals were immunized using 10 ?g of gWizHBs. The cytokine profile also showed high levels of TNF?, IFN ?, and IL2 and CD69 expression in the group of animal immunized using a dose of 10 ?g. Conclusion: Intramuscular injection of the modified DNA-based vaccine encoding HBsAg of 10 ?g dose in mice induced both high humoral and cellular immune responses.