The immune system sometimes plays on the side of the tumor
Scientists at the University of Pennsylvania, working under the guidance of Professor John Lambris (John Lambris), have found that some proteins of the immune system contribute to the growth of tumors. They found that instead of fighting tumors, the protein C5a, synthesized during the immune response to a developing tumor, helps it create a "molecular shield" against T lymphocytes.
Protein C5a is part of the complement system – one of the systems that protect the body from pathogens. When it is activated, the proteins of the system cleanse the body of microbes and foreign cells. Many approaches to cancer treatment are based on stimulation of antitumor immune response.
Until now, experts believed that the complement system ensures the elimination of tumor cells. The authors found that in some cases, depending on the type of tumor and the specific environment in which it develops, the complement system, on the contrary, stimulates the growth of tumors.
In experiments on a mouse model, they showed that activation of the complement system in tumor tissue triggers the synthesis of the C5a protein, which attracts myeloid suppressor cells to the tumor zone. These cells block the functioning of CD8 T lymphocytes attacking the tumor.
Blocking the C5a receptor on the cell surface slows down tumor growth as successfully as taking the chemotherapy drug Paclitaxel. This discovery indicates the possibility of developing new methods of antitumor therapy that have fewer side effects than chemotherapy.
According to Lambris, scientists are currently trying to introduce tumor immunotherapy and antitumor vaccines into practice, but most of these attempts end in failure. The authors demonstrated a possible mechanism for solving this problem. They are currently testing the approaches they have developed on five cancer models.
Portal "Eternal youth" http://vechnayamolodost.ru / based on ScienceDaily – Immune System Can Hurt As Well As Help Fight Cancer, Study Shows 03.10.2008