Ben-Gurion University of the Negev..
(photo credit: ISRAEL'S FOREIGN AFFAIRS MINISTRY)
Scientists at Ben-Gurion University of the Negev have identified how lymphocytes (a type of white blood cells) differentiate between sick and healthy cells.
The study proved that by placing lymphocytes near artificial cells that had affixed nanowires – rod-like miniature structures that are only a few nanometers long – lymphocytes reacted both chemically and mechanically to the cells.
The research was led by Dr. Mark Schvartzman of BGU’s Department of Materials Engineering and Prof. Angel Porgador of the Department of Microbiology, Immunology and Genetics, and published in the peer-reviewed journal Advanced Materials. Dr. Guillaume Le Saux, Dr. Uzi Hadad, Avishay Edri and Netanel Bar-Hanin were also part of the team.
The group formulated a way to coat the nanowires with markers that were attached to the sick cells. The nanowires were then able to recognize artificial cells as being chemically identical to real sick cells, triggering a fight response. The antigen molecules used as markers encourage production and are recognized by antibodies – Y-shaped proteins that are used by the immune system to fight pathogens, such as bacteria or viruses.
When the lymphocytes were placed next to artificial cells, they attached themselves to the nanowires, bending them and causing the cells to release large amounts of toxic substances that are used to kill viral cells in the human body.
Schvartzman noted: “We have known for a long time that lymphocytes use chemical excretions to identify and kill ‘enemy’ cells inside the body, but this was the first time we were able to observe the mechanical process that occurs at the same time. Observing this process has been impossible, mostly due to the difficulty in reproducing the mechanical features of probed cells, whose surface is landscaped with complex nanometric shapes. The force applied by lymphocytes on the target cell is extremely small... often scaled in units of piconewton [one-trillionth of a Newton], so detecting and measuring the level of a force exerted by the lymphocyte on the target cell has been extremely challenging.”
The unearthing of this mechanism is crucial to research in immunotherapy, which has been a growing focus of cancer treatment in recent years. Immunotherapy aims to fight cancer by using substances that trigger a patient’s immune system. It is much safer and more effective than chemotherapy, and allows treatments to be personalized for each patient, tailored to his or her own immune system.
So far, such research has been hindered by the inability of scientists to understand the mechanism by which lymphocytes recognize sick cells or tumors.
“We still have barely scratched the surface of our knowledge of the human immune system,” Schvartzman said. “But the discovery of this mechanism is an important step and will serve as a springboard for further research that will expand our basic understanding that is necessary for the development of future immunotherapies.”