Salmonella enters the body through spoiled food and causes serious poisoning. Oncologists were aware that "harmful" bacteria purposefully colonize tumors. Recently, scientists have developed a salmonella strain that directs the immune system against malignant neoplasms.
How does salmonella help fight cancer?
Scientists at the Helmholtz Center for Infectious Research have tried to use Salmonella's special property to treat cancer. Experts have developed a strain of salmonella that causes only a harmless infection and helps in the fight against tumors.
Cancer is one of the most common causes of premature death worldwide.
Especially in a society whose members are getting older, cancer is becoming increasingly important. There is no effective therapy for many types of cancerous tumors.
How does the immune system respond more effectively to tumors?
German scientists have been looking for ways to make the human immune system more sensitive to tumors. To cause this effect, scientists used bacteria of the species Salmonella enterica.
In people with cancer, salmonella colonize tumor tissue. Nevertheless, there is a big drawback: salmonellosis progresses rapidly and causes potentially fatal complications.
To effectively control the tumor, a salmonella strain must elicit a strong immune response and not harm the body. Bacteria have been genetically modified by scientists step by step. Experts tried to achieve an optimal balance between safety and an adequate immune response.
The various properties of salmonella have been greatly altered. With the help of modern technologies, specialists were able to reduce the mobility of bacteria and, therefore, their danger to human health.
Bacteria shell has been changed
In order for the human immune system to recognize bacteria, medical workers have made certain changes to the Salmonella membrane. Some proteins in the outer shell were "edited."
Lipopolysaccharides, which consist of chains of sugar and fat, are fixed in the membrane, experts say. Such molecules are located on the surface of bacteria. They are usually recognized by the human immune system as "intruders."
In order to invisibly penetrate the host organism, various Salmonella enzymes are able to break down fat chains. Thus, they can hide from the immune system during infection.
Certain enzymes that cause the breakdown of fats were eliminated in an experiment on the used Salmonella strain. Therefore, bacteria were well recognized and eliminated by immunity.
The balance between weakening bacteria and the strength of the immune response
Researchers have integrated several genetic changes into the Salmonella strain. Then, experts began to study the therapeutic effect on mice. Scientists say they managed to find the right balance between weakening bacteria and the strength of the immune response.
One of the problems is that people who have already come into contact with bacteria have developed immunity to them. Therefore, they may no longer respond to therapeutic salmonella.
A therapeutic bacterial strain must be able to overcome the body's own defenses. Salmonella infections are relatively common in some areas with poor hygiene conditions. Therefore, people in underdeveloped countries will react worse to medicine.
Patent for modified Salmonella strain pending
Other scientists have developed a strain that activates the body's own defenses even in mice with Salmonella immunity. Professor Weiss says that even tumors that were previously resistant to the Salmonella strain were destroyed by the immune system.
The Salmonella strain modified by doctors has already been patented. The bacterium is safe and at the same time effective enough for use in the treatment of tumors. The modified bacterial strain should now be tested in further studies.
