Background:
Streptococcus pneumoniae is a leading cause of pneumonia, mostly in children less than five years
and elderly people. Although the pneumoniae polysaccharide vaccine (PPV) and pneumonia conjugate vaccines (PCV) are
the efficient pneumococcal vaccine in adult and children groups, but the serotype replacement of S. pneumoniae strains
causes the reduction in the efficacy of PPV and PCV vaccines. Epitope-based vaccines are a promising alternative to the
present capsular antigen vaccines.
Methods:
In this study, we evaluated cellular and humoral immune responses induced by
our novel designed multi-epitope vaccine in BALB/c mice. CD8+ cytolytic T lymphocytes (CTLs) epitopes were selected
from PspA and CbpA antigens, and CD4+ helper T lymphocytes (HTLs) epitopes were chosen from PhtD and PiuA
antigens. PorB, the TLR2 agonist, as an adjuvant, was employed to increase the immunogenicity of the vaccine.
Results and conclusion:
The high levels of specific anti-peptide vaccine IgG and an increase in the level of IgG2 in the vaccinated group
demonstrated our vaccine could elicit a robust antibody production. The significant increase in IFN-γ, IL-2, TNF-α, IL-4,
IL-6, and decrease in IL-10 showed that, the designed vaccine could be proposed as the efficient preventative pneumococcal
vaccine in the mouse model.