A substance that triggers asthma in laboratory mice has been discovered by a group of Japanese researchers, according to an article published Friday in the U.S. journal Science.
The substance, prostaglandin D2 (PGD2), brought on asthma by transmitting signals to cells in the lungs and other airways in the body, the researchers said.
If a drug capable of blocking the signals can be developed, the discovery may possibly lead to a cure for asthma and other ailments which manifest similar symptoms, such as hay fever and inflammation of the skin caused by atrophy.
"We mainly understand how PGD2's movement is blocked," said Kyoto University's Shu Narumiya, one of the 18 researchers. "If it can be used (to make) a drug, it would be useful in treatment."
PGD2 is secreted by certain immune cells after exposure to antigens in the environment.
Scientists already knew that large amounts of the substance are released in the body when allergies strike. However, its exact function was previously unknown.
The researchers bred a group of mice which lacked receptors to which PGD2 binds. They then triggered allergic reactions in the bronchial tubes of the mice as well as in a control group of mice.
The control group developed allergic reactions while the modified mice did not.
The researchers learned that when PGD2 is continuously exposed to allergy-causing antigens, it binds to cells in the lungs and other air passages in the body.
When that happens, the cells release substances that attract nearby lymphocytes, causing inflammation and other nervous reactions associated with allergies.