Illustrative Example of Enveloped Viruses (purple) Approaching Human Cells (red): Lipid membranes are a key part of the viral envelope that plays critical roles in the life cycle of many medically important viruses.

Viruses are small infectious agents that replicate only inside the living cells of other organisms. They are 100 times smaller than a single bacterial cell and 1,000 times smaller than a human blood cell.

Viruses have three main parts:
  • Genome: The core of the virus within the DNA or RNA that makes the virus unique and helps it multiply;
  • Protein coat: A protective covering that surrounds the genome;
  • Lipid envelope: An additional covering around the protein coat, where the virus interfaces with the environment. Viruses with this feature are called enveloped viruses; many medically important viruses fall into this category.
In order to infect human or animal cells, viruses need to first enter the cells. They do this by attaching to a receptor on the cell surface. The viral genome then hijacks that cell’s machinery for its own replication. Because an infected cell produces viral particles instead of what the cell needs to survive, this process causes damage to the cell and illness to the host.

There are six basic steps that all infecting viruses follow as part of the virus life cycle:
  • Adsorption: A virus particle attaches to a host cell;
  • Entry: The particle inserts its genome into the host cell;
  • Translation: The invading genome takes over the cell and recruits the host’s enzymes;
  • Replication: The hijacked cellular enzymes start making new virus components;
  • Assembly: The virus components created by the cell come together to form new virus particles;
  • Release: The newly formed virus particles exit the cell and search for a new host cell to continue the replication process.
Because the viral envelope is shared among many viruses and cannot mutate to grow resistant to drug treatment (even if a virus mutates, envelope components, which are host-cell derived, do not), it is the Achilles heel of viruses — one that TSG’s technology successfully attacks.

TSG is developing a unique set of membrane-active, antiviral peptides that seek out and disrupt enveloped viruses. By targeting the viral envelope with high potency and selectivity, our technology forms the basis of novel broad-spectrum antiviral solutions with the potential to counter unpredictable viral threats that otherwise could not be addressed by vaccines or conventional antiviral drugs.