Toward a broadly protective influenza vaccine

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• Inactivated influenza virus vaccines primarily induce antibody responses, offering limited protection against antigenically drifted seasonal strains and novel pandemic influenza A viruses.
• Antibody escape variants and zoonotic influenza A viruses (e.g., H5N1) pose significant public health threats due to vaccine limitations.

Discussion:

• Influenza A virus-specific CD8+ T cell memory, directed at conserved internal viral proteins, can promote viral clearance and reduce disease severity in preclinical models.
• Pre-existing CD8+ T cell immunity does not prevent infection but can mitigate its impact, suggesting a complementary role to antibody-based immunity.

Key Insights:

• Individuals without prior avian influenza A (H5N1) virus exposure exhibit cross-reactive CD8+ T cell memory against a broad spectrum of H5N1 peptides.
• This cross-reactivity indicates that CD8+ T cells recognize conserved epitopes, even in naive populations.

Outlook:

• Peptides derived from conserved influenza A virus proteins can be utilized to engineer a CD8+ T cell component for next-generation influenza vaccines.
• Integrating CD8+ T cell induction into current antibody-focused vaccine strategies could enhance protection against diverse and emerging influenza A virus threats.