Influenza cure research

This approach focuses on methods that prevent the influenza virus from replicating after it has entered a host cell. Techniques include the use of restriction enzymes or other molecular tools that disrupt viral genetic material.

• Influenza genome: Single-stranded, negative-sense RNA virus with 8 gene segments.
• Key viral enzymes targeted by antivirals:
  • Neuraminidase (NA) – enables virus release from infected cells.
  • RNA-dependent RNA polymerase (RdRP) – required for replication.
• Approved antiviral drugs:
  • Oseltamivir (Tamiflu) and Zanamivir (Relenza) – neuraminidase inhibitors.
  • Baloxavir marboxil (Xofluza) – inhibits viral cap-dependent endonuclease.
• Experimental approach:
  • CRISPR-Cas13 has been explored for cleaving RNA viruses like influenza.
  • RNA interference (RNAi) has shown promise in silencing viral gene expression.

Compounds such as soaps, salts, and surfactants exploit the structural differences between viral protein coats and the human cell lipid bilayer. These agents can destabilize or inactivate the viral envelope, thereby preventing the virus from injecting its genetic material into host cells.

• Influenza virus structure:
  • Surrounded by a lipid envelope derived from host cells, embedded with glycoproteins: Hemagglutinin (HA) and Neuraminidase (NA).
• Mode of action of surfactants:
  • Soap/surfactants disrupt lipid envelopes via emulsification and denaturation, making the virus non-infectious.
  • Alcohol-based disinfectants (60%+ ethanol) denature viral proteins and dissolve lipid membranes.
• Experimental insights:
  • Amphipathic peptides have been investigated to disrupt viral envelopes.
  • Salt solutions (e.g., hypertonic saline) can interfere with membrane fusion and viral entry in cell models.

This category includes approaches aimed at boosting the host’s immune response—either broadly or in a targeted manner—against the influenza virus.

• Immune-boosting agents:
  • Interferon-alpha: Administered intranasally as a prophylactic.
  • Vitamin D and zinc supplementation: May improve innate immune response.
• Immune memory stimulation:
  • Trained immunity: Concept of enhancing innate immune response using agents like BCG vaccine (under investigation).
• Immunomodulators:
  • Toll-like receptor (TLR) agonists: Studied for rapid activation of innate immunity against influenza.

Although technically a form of immune enhancement, vaccine development deserves its own category due to its focus on the virus rather than the host. Vaccines aim to prime the immune system to recognize and combat the influenza virus before full-blown infection occurs.

• Vaccine types:
  • Inactivated influenza vaccines (IIV) – most common, intramuscular.
  • Live attenuated influenza vaccine (LAIV) – nasal spray.
  • Recombinant vaccines (RIV) – grown in insect cells, faster production.
• Strain selection:
  • Updated annually based on WHO surveillance of circulating strains.
• Challenges:
  • Antigenic drift and shift – cause strain variation and pandemic potential.

• Next-generation efforts:
  • mRNA-based flu vaccines under clinical trials (e.g., Moderna’s mRNA-1010).
  • Universal flu vaccine research focusing on conserved HA stem region.

In severe influenza cases, particularly among young and healthy individuals, an overactive immune response known as a cytokine storm can cause fatal damage. Controlled immunosuppression aims to reduce this risk by modulating the immune response to prevent excessive inflammation while still allowing viral clearance.

• Cytokine storm mechanism:
  • Overproduction of cytokines (IL-6, TNF-alpha, IFN-gamma) damages tissues, especially lungs.
• Flu examples:
  • 1918 H1N1 and H5N1 avian flu caused deaths primarily via cytokine storms in healthy adults.
• Treatment strategies:
  • Corticosteroids (e.g., dexamethasone) – controversial but sometimes used.
  • IL-6 inhibitors (e.g., tocilizumab) – under exploration in viral infections.
  • Macrolides (e.g., azithromycin) – have immunomodulatory properties.

This approach involves the selective elimination of cells already infected with the influenza virus to halt viral reproduction. This can be achieved through targeted therapies that induce apoptosis (programmed cell death) in infected cells.

• Targeted cell death:
  • Apoptosis inducers: Aim to selectively trigger cell death in infected cells.
• Promising research:
  • TRAIL (TNF-related apoptosis-inducing ligand) pathway activation.
  • Host-directed therapies targeting specific pathways like PI3K-AKT-mTOR, used by viruses to hijack host machinery.
• Viral load control:
  • Drugs that promote autophagy or inhibit translation of viral proteins can suppress infected cell productivity.
• Limitations:
  • Balancing efficacy vs. toxicity to healthy tissue is a major challenge.