The Theory of Nothing

How do viruses work?

How do viruses work?

The existence of viruses, which cannot be seen in an optical microscope, was not known or suspected until late in the nineteenth century. When an extract of an infectious agent taken from an ill person was run through a filter capable of filtering bacteria, which could be seen in an optical microscope, the filtered solution still caused infection, so the scientists of the day assumed that there was a tiny infectious agent that they couldn’t see. At this time in 1892, there was no way to see a virus. They’re just too darn small. It wasn’t until the invention of the electron microscope that we could see these little devils.

The reason that a virus is so small is because it’s not alive in the same sense as a bacterium. Bacteria can reproduce by mitosis, an asexual type of reproduction in which one bacterium simply splits into two bacteria. A virus can’t do that because it doesn’t have the cellular mechanisms necessary for mitosis.

Mitosis is a very complicated process, but it happens in the cell’s nucleus where there are special proteins and lipids that help in this amazing process of reproduction.

A virus is essentially a DNA or RNA fragment, or a naked chromosome, encased in a protein coat or sheath for protection. In order for the virus to make more of its kind it must infect a cell (penetrate it all the way to the nucleus) and take over the cell’s reproductive machinery.

How does it do this? Many viruses work by penetrating the outer membrane of a cell, but first they must attach to the cell’s outer membrane. This is accomplished by finding a specific receptor protein section on the cell membrane and fitting into it like a glove, so to speak. This is a complicated microbiological process using matching protein structures that can bind together. This is how a specific virus finds the kind of cells it has evolved to infect. Yes, viruses evolved along with us, and they are smart little devils when it comes to adapting.

After attachment, the virus uses membrane fusion (it can merge its sheath lipids with the cell membrane’s lipids to become one membrane) to open up a pore or entry into the cell’s wall it’s designed to infect. Once a portal is created, the virus injects its RNA fragment into the cell so that it gets into the cell nucleus. The cell nucleus is where the real action of a cell takes place. This is where the cell has its own DNA for the process of mitosis or replication. Well, the darn virus RNA fragment acts like a bully and takes over this process and starts using the stuff in the cell nucleus to make more of it by creating duplicate virus RNA fragments, which then make use of the cell’s machinery to synthesize the protein coats necessary to protect the viral RNA. Eventually, this process causes the cell to die and burst open so that all of the new viruses can escape to infect more cells. You can see how this infection can escalate and go viral, no pun intended.

How do viruses mutate? This is another complicated question, but it’s mainly because the virus has a RNA fragment that can mutate just like it does in every living creature on Earth. Some viruses mutate rapidly. The flu and common cold viruses are in this category. However, the real way that they mutate is by changing the protein coat or sheath that protects the RNA fragment. This protein sheath sometimes contains lipids and sugars that can be mutated.

All of these molecules that make up a virus coat can be used to create a vaccine. A vaccine works by killing the virus--if that’s the correct way to say it--so that it won’t infect us.  It does this by making our immunes systems go after the virus coat by creating and inciting antibodies for this purpose. Antibodies are specific to a particular virus’ coat and work by attaching to it and taking it out of action. In other words, the antibody finds the virus, grabs it and tells it ‘You’re out of here!’ The only defense that the virus has against this is to change its coat so the antibodies no longer recognize it or attack it. Our only defense is for our immune system to make new antibodies that will attack the virus’ new coat. A vaccine helps in this process. Most vaccines are dead viruses, and they induce our immune system finds these intruders and create an antibody to attach to them. Once there are enough antibodies, our bodies have a good army to fight these invader viruses.

If this sounds like a perpetual war, it is, and it’s been going on for eons. The best defense is to get all of the vaccinations that you can.

Thanks for reading.