"Confused" immune cells attack the lungs

Chronically ill due to misguided helpers

A T-cell (blue) attacks an epithelial cell of the lung mucosa (red) GBF
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Malfunctioning immune cells can be the cause of severe pneumonia. This has now been proven by scientists from the Gesellschaft für Biotechnologische Forschung (GBF) in Braunschweig. They report on their findings in the current issue of the American Journal of Respiratory and Critical Care Medicine (AJRCCM).

The researchers investigated mice that are prone to chronic inflammation of the lung mucosa in the study. Result: Immune cells of the type of the so-called CD 4+ T-cells trigger such a disease, if they - erroneously - proceed against the own body tissue instead of invading pathogens.

As "interstitial lung disease", ILD for short, physicians refer to a class of various disorders and diseases of the alveoli and the connective, lymphatic and vascular tissue of the respiratory organs. Various forms of pneumonia are also summarized under the generic term ILD. Not only humans but also mice can develop ILD. In these animals, Professor Jan Buer's GBF working group - together with colleagues from Yale University in the USA - has now shown what scientists have long suspected but not yet demonstrated: the active role of out-of-control CD 4+ T cells in the development of some forms of ILD.

Better understand immune reactions in the lungs

"For our research, we have crossed two mouse breeding lines, " explains GBF scientist Dunja Bruder, "the first mouse type carried a special protein molecule on the cells of the lung mucosa - a so-called antigen. The second strain produces aggressive immune cells against this antigen. The result is mice whose defense system attacks their own lung tissue. "These animals then developed symptoms of ILD.

Shortly after the misdirected immune reaction, the juxtaposition of antigen and defense cells directed against it also triggers mechanisms of immune tolerance: anti-inflammatory messengers are released, defense reactions are attenuated and slowed down. "After a severe acute onset of the disease, the symptoms abate and the disease becomes chronic, " says Dunja Bruder. display

The study of this chronic disease, the scientists hope, will lead to a more comprehensive understanding of immune responses in the lungs. "Not only in ILD, but also in many other lung diseases such as allergic asthma mismanagement of immune cells play a role, " explains Jan Buer. "The cells of diseased mice are largely the same genes turned on as in sick people. If we understand these processes better, we can also develop new potential approaches to healing. "

(idw - Society for Biotechnological Research (GBF), 16.12.2004 - DLO)