CD40 stimulation activates CD8+ T cells and controls HBV in CD4-depleted mice

Area of Science:

• Immunology
• Hepatology
• Virology

Background:

• Hepatitis B virus (HBV) treatment is hindered by persistent covalently closed circular DNA (cccDNA).
• Antiviral interventions do not affect the cccDNA pool, necessitating novel therapeutic approaches.
• Targeting antigen-presenting cells via CD40 stimulation is explored for sustained HBV control.

Purpose of the Study:

• To evaluate CD40 stimulation as a therapeutic strategy for HBV control in a mouse model.
• To investigate the role of CD4+ and CD8+ T cells in CD40-mediated HBV control.
• To assess the potential of combining CD40 stimulation with other immunotherapies.

Main Methods:

• Mice were infected with HBV using adeno-associated virus (AAV-HBV) and treated with agonistic CD40 antibody.
• CD4-depleting antibody was administered alongside CD40 antibody to assess CD4+ T cell impact.
• Viral antigens, liver HBV mRNA, and HBV-specific CD8+ T cells were quantified.

Main Results:

• CD40 stimulation in CD4-depleted mice led to HBsAg and HBeAg clearance and reduced liver HBV mRNA.
• CD8+ T cells were essential for CD40-mediated HBV control; their depletion resulted in HBV persistence.
• CD40 stimulation combined with VSV-MHBs immunization further enhanced HBV control in chronic models.

Conclusions:

• CD40 stimulation is a promising therapeutic strategy for sustained HBV control.
• CD8+ T cell activation is critical for CD40-mediated antiviral efficacy.
• Depletion of CD4+ T cells unexpectedly improved CD40-mediated HBV reduction, suggesting a complex regulatory role.