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Scientists Discover T Cells That Recognize Mutating Flu Viruses, Paving the Way for Universal Vaccines
In a breakthrough for influenza research, scientists have discovered immune cells that can recognize flu viruses even as they mutate, raising hopes for a longer-lasting vaccine and universal protection against future flu pandemics.
The flu virus constantly evolves, meaning that immunity from past infections or vaccinations may not fully protect against new strains. These frequent mutations are why flu vaccines must be updated annually. However, new research suggests that certain immune cells, a subset of T cells, might provide broader and longer-lasting protection against influenza.
Cross-Reactive T Cells Offer Hope
Research led by the Peter Doherty Institute for Infection and Immunity (Doherty Institute) and Monash University has uncovered how specific T cells can detect multiple flu strains, including those that have evolved over a century. This process, known as cross-reactivity, could be crucial in developing more effective and lasting immunity against influenza.
The study, published in Science Immunology, analyzed samples from individuals infected with different flu viruses and identified a subset of T cells that recognize a protein present in influenza A viruses, from the 1918 Spanish flu to the latest 2024 H5N1 strains.
Understanding the Molecular Mechanisms
Dr. Oanh Nguyen, Senior Research Fellow at the Doherty Institute and co-author of the study, explained how these T cells function.
“We tested how people’s T cells respond to a specific part of the influenza virus that changes frequently. Over the last 100 years, this region has evolved into 12 different forms,” said Dr. Nguyen. “We found that some individuals have T cells that can recognize up to nine of these variants, while others have T cells that can only detect a couple.”
Professor Jamie Rossjohn, an immunologist at Monash University and co-senior author of the study, detailed the advanced techniques used in the research.
“We used an advanced technique called crystallography to determine how T cells see flu viruses at the molecular level. We observed specific interactions between the T cells and the flu proteins that determine why some T cells are better at detecting a wide range of strains than others,” said Professor Rossjohn.
Implications for a Universal Flu Vaccine
Influenza remains a major global health threat. According to the World Health Organization (WHO), flu causes 3 to 5 million cases of severe illness and up to 650,000 respiratory deaths annually, particularly among vulnerable populations.
Professor Katherine Kedzierska, Head of the Human T Cell Laboratory at the Doherty Institute, emphasized the importance of these findings for future vaccine development.
“This research is hugely significant. It shows how certain T cells can recognize multiple flu strains, which is a big step towards understanding universal protective immunity—not just for the flu, but potentially for other viral diseases too,” said Professor Kedzierska. “Harnessing these cross-reactive responses could be the key to a vaccine that offers longer-lasting protection and reduces the risk of future flu pandemics.”
Looking Ahead
While these findings deepen our understanding of how T cells react to changing flu viruses, they also have implications for other rapidly evolving viruses, such as SARS-CoV-2. The next step in this research will be to explore how these immune responses can be harnessed for vaccine development and whether they can be applied to other infectious diseases.
Disclaimer:
This article is based on current research findings and expert opinions. While the study presents promising insights into immune responses and vaccine development, further research and clinical trials are necessary before a universal flu vaccine can be developed and made widely available.
More Information: Sergio M. Quiñones-Parra et al, Molecular determinants of cross-strain influenza A virus recognition by αβ T cell receptors, Science Immunology (2025). DOI: 10.1126/sciimmunol.adn3805
