Australian scientist claim that the global population is equipped to fight H5N1 infections via CD8 T-cells
Nikhil Prasad Fact checked by:Thailand Medical News Team Nov 23, 2024 3 hours, 41 minutes ago
Medical News: Rising Concerns Over Avian Influenza
A recent H5N1 avian influenza outbreak in the United States has reignited fears about the potential for another global pandemic. This highly pathogenic avian flu virus, responsible for severe outbreaks in poultry, is now affecting cattle in multiple U.S. states, with reported cases of human infection through cow exposure. The strain, known as clade 2.3.4.4b, has also spread across Europe, Africa, and South America. In Southeast Asia and Australia, other H5N1 variants, such as clade 2.3.2.1a, are also circulating.
Australian scientist claim that the global population is equipped to fight H5N1 infections via CD8 T-cells
The lack of licensed vaccines against H5N1 for human use further complicates the situation. Current seasonal influenza vaccines, which target H1N1 and H3N2 strains, are unlikely to provide substantial protection against avian viruses. Amid these challenges, groundbreaking research from La Trobe University and Monash University in Australia suggests a ray of hope: the human immune system might already be equipped to fight H5N1 through the power of CD8+ T cells. This
Medical News report delves into their findings.
The Role of CD8+ T Cells
CD8+ T cells play a crucial role in protecting against influenza, enhancing viral control, and reducing disease severity. Researchers Emma J. Grant and Stephanie Gras compiled a list of immunogenic CD8+ T cell epitopes from influenza A, focusing on their conservation in H5N1 viruses. By analyzing the sequences of these epitopes against recent H5N1 strains, they sought to understand the extent of pre-existing immune protection in humans.
Key Findings of the Study
The researchers found that over 64% of CD8+ T cell epitopes from influenza A viruses are highly conserved in H5N1 strains, showing more than 90% sequence identity. These epitopes were identified across 18 of the 30 most prevalent human leukocyte antigen (HLA) molecules worldwide, collectively covering more than 100% of the global population.
Proteins such as NP (nucleoprotein), M1 (matrix protein), PB2 (polymerase basic protein 2), NS1 (non-structural protein 1), and PB1 (polymerase basic protein 1) exhibited the highest epitope conservation rates. In contrast, surface proteins like HA (hemagglutinin) and NA (neuraminidase) showed significantly less conservation, emphasizing the importance of targeting internal proteins for broader immunity.
Why Epitope Conservation Matters
Epitopes are the specific regions of a virus that the immune system recognizes and attacks. Conserved epitopes remain unchanged across different virus strains, making them reliable targets for immune defense. The study’s findings indicate that people with common HLA molecules might already possess a degree of immunity to H5N1, reducing the risk of severe disease.
For instance, the NP protein, which had a 70% conservation rate, is essential for viral replication and immune evasion, making it a k
ey target for T cells. Similarly, the PB1 protein showed an impressive 84% conservation, suggesting strong potential for cross-protection.
Implications for Vaccine Development
The lack of vaccines specifically targeting H5N1 highlights the importance of leveraging CD8+ T cell responses. Unlike antibodies, which often target rapidly mutating surface proteins, T cells focus on internal proteins that are more stable across strains. By incorporating conserved epitopes into vaccine designs, researchers could develop universal vaccines offering protection against both seasonal and pandemic influenza strains.
Challenges and Future Directions
While the study offers promising insights, it also highlights gaps in our understanding of T cell responses to H5N1. Epitopes from certain proteins, such as M2, showed minimal conservation, indicating areas where the immune system might struggle to mount an effective response. Moreover, the impact of mutations in conserved epitopes on immune recognition requires further investigation.
The findings also underscore the need for population-specific studies to ensure vaccine efficacy across diverse genetic backgrounds. For instance, HLA molecules vary significantly among populations, influencing how individuals respond to different epitopes.
Conclusions
This research marks a significant step toward understanding the immune system’s ability to combat H5N1. By identifying conserved CD8+ T cell epitopes across prevalent HLA molecules, the study provides a foundation for developing vaccines and therapies that harness the body’s natural defenses. The findings suggest that despite the lack of H5N1-specific vaccines, pre-existing T cell immunity might offer a degree of protection, potentially mitigating the impact of future outbreaks.
The study findings were published in the peer-reviewed journal: Clinical & Translational Immunology.
https://onlinelibrary.wiley.com/doi/10.1002/cti2.70017
For the latest H5N1 News, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/news/canada-s-first-h5n1-human-infection-linked-to-d1-1-genotype-not-the-d3-13-variant-found-in-american-cows
https://www.thailandmedical.news/news/reassorted-strain-of-h5n1-bird-flu-virus-discovered-in-cambodia
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