A protective role for dengue virus-specific CD8+ T cells.

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• Dengue virus (DENV) infection causes a spectrum of illness, from mild fever to severe hemorrhagic fever.
• While T cells are linked to severe secondary DENV infections, their role in primary infection and protection remains unclear.

Purpose of the Study:

• To investigate the role of CD8(+) T cells in the host immune response during primary dengue virus infection.
• To explore the potential of enhancing anti-DENV CD8(+) T cell responses through immunization.

Main Methods:

• Used a mouse-passaged DENV2 strain (S221) in wild-type and IFN-alpha/betaR(-/-) mice.
• Depleted CD8(+) T cells to assess their impact on viral load.
• Mapped T cell epitopes and analyzed T cell effector functions (IFN-gamma, TNF-alpha, cytotoxicity).
• Evaluated the effect of epitope-based immunization on viral clearance.

Main Results:

• CD8(+) T cell depletion led to significantly higher viral loads in infected mice.
• Identified 12 DENV epitopes recognized by CD8(+) T cells, with a conserved immunodominance hierarchy.
• DENV-specific CD8(+) T cells demonstrated effector functions including cytokine production and cytotoxic activity.
• Immunization with selected epitopes enhanced viral clearance in mice.

Conclusions:

• CD8(+) T cells play a critical role in controlling primary DENV infection.
• Targeting DENV-specific CD8(+) T cell responses via immunization can improve viral clearance.
• These findings support the development of DENV vaccines that elicit robust cell-mediated immunity.