Highly conserved influenza T cell epitopes induce broadly protective immunity

Area of Science:

• Immunology
• Vaccinology
• Bioinformatics

Background:

• Annual influenza epidemics cause significant global morbidity and mortality.
• The high mutation rate of influenza necessitates yearly vaccine reformulation.
• Current vaccines target strain-specific antigens, limiting cross-protection.

Purpose of the Study:

• To identify conserved T cell epitopes across diverse influenza A strains.
• To develop and test T cell-targeted vaccines for universal influenza protection.
• To demonstrate the potential of a broadly protective, multi-epitope influenza vaccine.

Main Methods:

• Utilized immunoinformatic tools to identify conserved pan-HLA-DR and HLA-A2 restricted T cell epitopes.
• Screened >50 diverse influenza A strains for conserved epitopes.
• Developed and tested dendritic cell and DNA vaccines encoding conserved epitopes in HLA transgenic mice.

Main Results:

• Identified highly conserved influenza peptides predicted to be HLA-A2 restricted and immunogenic.
• Discovered conserved CD4 epitopes recognized by human CD4+ T cells.
• Vaccines induced protective immunity against H1N1 and H3N2 influenza challenges in mice.

Conclusions:

• Conserved T cell epitopes can elicit broadly protective, heterotypic immunity against influenza.
• This strategy supports the development of universally relevant, multi-epitope T cell-targeting influenza vaccines.
• Proof-of-principle established for a universal influenza vaccine approach.