Definitely a breakthrough in medicine: Scientists for the first time have been able to document an organ-specific innate immune system. As published in the April 18 edition of the journal Immunity, scientists at the University of California, San Diego (UCSD) School of Medicine reported the unique mechanism by which the lung shapes its defensive strategies against microbial invasion.

"This innate immune response is specific to the lung, and was probably designed to minimize collateral damage to lung tissue caused by unchecked inflammation," said Eyal Raz, M.D., Professor of Medicine at UCSD School of Medicine.

The body's respiratory tract is constantly exposed to inhaled particles or microorganisms. The alveola - tiny air sacs in the lung where exchanges of gases between the respiratory and circulatory systems takes place - are protected from invading microbes by the alveolar macrophage.

Macrophages are white blood cells involved in the inflammatory response throughout the body, cells normally on the alert for invaders to kill. Alveolar macrophages are unique among macrophages in the body, because their activation is inhibited by TGFb, a compound expressed in the lung by epithelial cells.

Understanding the mechanism by which the lung's innate immune system operates will prove to be essential in combating any novel microbial agents that could infect the lower airways, such as a new flu strain or bioterrorist agents and maybe all other elements that harm the lungs.

Source: EurekAlert