Why are dendritic cells called dendritic cells

The discovery of the dendritic cell

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The main job of neutrophils is to kill bacteria and other microorganisms in order to keep them from multiplying and penetrating deeper into the body. To do this, the neutrophils used special weapons, peptidases and oxygen radicals. "However, these are powerful weapons, like explosives, they also destroy the good cells around them." These detonations are one of the reasons that wounds are often the most painful in the days that follow.

In a wound, the blood vessels expand in order to be able to transport more cells to the site of the accident, more oxygen, more blood. The macrophages follow the neutrophils to the place of misery, they too are white blood cells, only larger, hence the name: macrophage means giant eating cell. A sub-form of the cell type that Elias Metschnikoff discovered in his starfish larva. Sabine Werner says: "The macrophages are the clean-up party." They clear up the battlefield and take what remains of the dead. "They eat them up." When the work is done, they leave the wound.

There, in the skin, but also in the stomach and lungs - wherever the inside is in close contact with the outside world - another cell creeps around, the importance of which had long been dismissed, like the thymus before Jacques Miller. In 1973 Ralph Steinman, a professor at Rockefeller University in New York, discovered the cell. It had delicate twig-like appendages. Therefore, Steinman wrote later, he had initially considered calling them Claudiazyten - "because my wife Claudia also has such long, attractive limbs". But then he called them dendritic cells, from Greek dendron, Tree. Steinman was convinced that these cells were extremely important for the immune system. Hardly anyone believed him.

In the early 1980s it ran a young Austrian through the rooms of Rockefeller University, he stopped in front of Steinman's office and knocked on the door. Up until then he had heard one thing above all about Steinman: that he was a madman. Colleagues whispered about the professor behind closed doors, at immunologist meetings they rolled their eyes as soon as he spoke. "Ralph was downright laughed at. Today one would probably speak of character assassination," says Gerold Schuler, the young Austrian from then, now 70. Schuler, internationally known cancer researcher and former director of the dermatological university clinic in Erlangen, says: "I still wanted to see Ralph . "

He moved from Innsbruck to New York and started working in Steinman's laboratory. They spent days and nights hunched over microscopes, doing experiments and discussing. "We were a small group of crazy people who were fascinated by Ralph," says Schuler. Steinman was humble and at the same time incredibly helpful. Once a week he went dancing with his wife Claudia. "Claudia always says I had a very special relationship with Ralph," says Schuler. "Well, he was Capricorn, I'm Capricorn. We just had to look at each other and we knew what the other was thinking."

For years he had made the pilgrimage with Steinman from congress to congress, together they tried to make it clear to the professional world what an all-important role the dendritic cell plays in the immune system.

The breakthrough came when Schuler tried to discover what had remained hidden for so long. He, as humble as Steinman, proved that dendritic cells exist in two states, immature and mature.

The difference between the two states: If, for example, an influenza virus has penetrated the lungs, immature dendritic cells ingest infected and dead parts of the lung cells. Danger signals triggered by the ignition bring them to the tire. The mature dendritic cells then attack the T cells, which attack the viruses.

The dendritic cells don't just send the T cells into battle. They also teach them to spare healthy body cells.

The process is of course much more complex in all its details, but perhaps in this case one should stick to Ralph Steinman, who, as Gerold Schuler explains, placed great emphasis on explaining difficult facts as simply as possible so that everyone could understand them understands. Steinman said: "The dendritic cells are the generals that control the entire immune response. They give the soldiers orders as to who is to be attacked and how." This is why they are so important: They are the cells that teach the body to distinguish between good and bad.

"When we were finally able to prove that, it was a sensation," says Schuler. Text books had to be rewritten, curricula changed. Ralph Steinman, laughed at for so long, had forever changed the understanding of the immune system.

In the spring of 2007, Schuler, who had been clinic director in Erlangen for twelve years, received an email from his friend Ralph Steinman. "Bad news", it was written there. Steinman wrote that doctors had diagnosed him with pancreatic cancer. Most people die from it within a year.

Schuler and his colleagues went out of their way to help Steinman. Together they wanted to defeat the tumor. They developed therapies, and indeed Steinman survived the first year, the second, the third, the fourth.