Targeting the Core: A Universal Flu Vaccine on the Horizon
Seasonal influenza, a yearly threat to global health, poses significant challenges. While current vaccines offer some protection, their effectiveness wanes as the virus mutates rapidly. This race against time necessitates constant updates, a resource-intensive process. A new approach, however, holds promise: targeting the flu virus’s core internal proteins, potentially paving the way for a universal, long-lasting solution.
Researchers at Oregon Health & Science University (OHSU) are spearheading this innovative strategy, leveraging the power of T-cells, a crucial component of the immune system. "The problem with the flu is that it is not a single virus," explains Dr. Jonah Sacha, Professor and head of the Patobiology division of the National Primates Research Center at OHSU. "It’s constantly evolving towards the next variant, and we’re always trying to catch up."
Current vaccines primarily focus on antibodies that target the virus’s surface proteins – hemagglutinin (HA) and neuraminidase (NA). These proteins are highly variable, leading to vaccine mismatch and reducing effectiveness. As research published in "Nature Communications" outlines, "while current antibody-based approaches can provide sterilizing immunity, they carefully focus on the sequences of HA and NA specifications of the subtype and, therefore, they are susceptible to the lack of antigenic correspondence with new strains that occur every year through the drift of the antigen or suddenly emerge with pandemic potential through genetic reorganization."
The OHSU team proposes a novel approach that targets internal structural proteins, less prone to mutation, recognized by cytotoxic T-cells in the lungs. These cells are adept at destroying infected cells, providing a more durable and broad-spectrum immune response. Their goal is to create a "universal" flu vaccine that offers long-lasting protection against a wide range of strains, regardless of surface protein variations.
This approach utilizes a modified cytomegalovirus (CMV), a common, harmless herpes virus, as a delivery vehicle. CMV naturally induces a strong immune response, boosting the vaccine’s effectiveness. The researchers insert fragments of influenza proteins into the CMV genome, creating a modified virus that safely delivers these antigens to the immune system.
Remarkably, this vaccine platform has shown success not only against seasonal flu but also against highly pathogenic avian influenza (HPAI) viruses, such as H5N1, which has a 52% documented mortality rate in humans. In studies with primates, researchers observed that the vaccine limited virus infection and lung damage, providing protection from this deadly infection.
"The inhalation of the H5N1 flu virus in the form of aerosol causes a cascade of events that can trigger respiratory failure," explains Dr. Simon Barratt-Boyes, Professor of Infectious Diseases, Microbiology, and Immunology at Pitt. "Immunity induced by the vaccine was sufficient to limit virus infection and lung damage, protecting monkeys from this serious infection."
This groundbreaking research offers a glimpse into a future where the threat of influenza is significantly reduced. Imagine a single vaccine providing lifelong protection against various flu strains, offering a substantial relief for individuals, healthcare systems, and global public health.
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