The first musings of a germ theory of disease can be traced back to the late Middle Ages (1000-1300 AD). The theory states that diseases can be caused by invisible little pathogens. Europe didn’t buy the theory until the late 1800s. As you can see, the tiny pathogens are real.
Bacteria really is our friend. Our digestive tract wouldn’t work without them. There is actually more bacterial DNA in our bodies than there is human DNA. But there are some bad players out there, like Samonella and Listeria. These are two nasty bugs that have caused nothing but suffering in humans. But that may soon change.
These two bacteria are especially sneaky. Not only do they enter our bodies and cause trouble, but they go further and enter our cells. They’re trying to evade detection by our immune cells by hiding inside our normal cells. Fortunately, the cells that they hide in have a way of sending out an “S-O-S” or distress signal to inform the immune cells, “I have bacteria in me!” The immune system then destroys the infected cell and the bacteria within. The immune system also gets riled up and goes on a search and destroy mission for any other traces of the bacteria. So what does this have to do with cancer?
There are two biotech companies that are trying to develop a cancer vaccine made up of custom-designed Listeria bacteria. When injected into humans, the bacteria enter the patient’s cells. When the invaded cells send out their distress signal to the immune system, the distress signal is different, and according to whatever the engineers have in mind. In this case, the distress signal tells the immune cells that a cancer cell has invaded the cell (it was really Listeria, designed to “look” like cancer). Theoretically, the immune system should set off on a search and destroy mission for cancer cells. Oh, I forgot to tell you, this vaccine would be injected into patients with cancer, of course. They can even design specific Listeria that will elicit specific distress signals, according to the type of cancer the patient has. The clinical trials will tell us whether it really works.