Culture of Salmonella sp. 3D illustration
With the pandemic we have learned many things. Some that should stay with us, such as that soap is one of the most powerful bactericides that exist. Which, curiously and according to a recent article, is something that our body already knew.
Because there are cells in our body that produce a protein with characteristics similar to those of soap, and that use it precisely to kill the bacteria that seek to invade the tissue in which they are.
When we think about our defenses, the immune system always comes to mind, and for good reason since it is our line of defense. But to a greater or lesser extent, all cells in our body have systems to protect themselves from infection.
With this idea, the authors of the article we are talking about began their experiments. The first thing they did was recreate human epithelial tissue in the lab. This epithelial tissue is the first layer of cells found by any bacterium that wants to infect us, and that is why it is interesting to understand how their defenses work.
The fact is that, to awaken the defenses of this tissue, you need a signal from the immune system. Cells of the immune system produce a substance known as gamma interferon, which awakens the response of cells.
Well, what the researchers wanted was to check what substances could be in the epithelium when faced with a well-known infection: salmonella, caused by the bacterium Salmonella sp. And what they did was check which genes were activated by the presence of gamma interferon, to later study which proteins were produced.
One that caught their attention is the APOL3 protein. When salmonella attacks the epithelium, APOL3 is produced, and this protein is capable of dissolving the bacterial cell membrane. And since the cell membrane is made up of fatty acids, it actually acts like soap.
But of course, the thing is not so simple. Because salmonella bacteria, like many others, have an outer layer, called the bacterial wall, that protects its cell membrane. And APOL3, by itself, is not able to pass through this protection of the bacteria.
However, APOL3 is not alone. In addition to this protein that acts like soap, another known as GBP1 is produced, which what it does is transport APOL3 through the bacterial wall, so that it can reach the membrane and dissolve it.
So our body already knew, long before the pandemic, that soap is very useful to prevent infections.