Influenza vaccines: T-cell responses deserve more attention

Abstract

Currently licensed influenza vaccines rely predominantly on the induction of strain-matched hemagglutination inhibition antibody responses. These vaccines have a proven record of safety and efficacy in preventing influenza-induced illness and complications. However, they do not confer protection to all vaccinated individuals, and the protection they afford is short-lived, particularly in older adults. Hemagglutination inhibition titers induced by these vaccines are considered correlates of protection, but recent data demonstrate that this is not always the case. It is clear that better insight is needed into the immune responses that correlate with protection against human influenza. Influenza vaccines that can induce cross-reactive cellular immune responses (CD4⁺ and/or CD8⁺ T-cell responses) might correct some of the shortcomings of currently used influenza vaccines. In the future, the use of infection-permissive and disease-modifying vaccines that allow for the induction of cross-reactive T-cell responses may become a valuable complement to the administration of trivalent inactivated influenza vaccines.

Keywords::

• cellular immunity
• correlates of protection
• cross-protection
• infection permissive
• influenza
• T lymphocyte

Acknowledgements

The authors thank Amin Bredan for editing and critical reading of the manuscript.

Financial & competing interests disclosure

Research related to M2e-based influenza vaccines in the group of X Saelens is supported by FWO grant 3G037510 and Ghent University grant BOF12/GOA/014. Part of the research on influenza vaccines in the laboratory of X Saelens is supported by research collaboration with Sanofi Pasteur. G Leroux-Roels was principal investigator of clinical studies of seasonal and pandemic influenza vaccines for the following manufacturers: Baxter, GlaxoSmithKline, Novartis and Sanofi-Pasteur. The Ghent University received sponsoring for the conduct of these studies. G Leroux-Roels also performed consulting services for Baxter, GlaxoSmithKline, Immune Targeting Systems and Novartis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.