Brake blocker
Immunotherapy of the new generation began to be tested on humans
Svetlana Maslova, Hi-tech+
Scientists from the University of California at Los Angeles have developed an experimental drug that allows you to use the full force of immunity against cancer and at the same time block its restraining mechanisms, namely regulatory T cells (Treg), which usually act as a brake on the immune system to prevent excessive activity.
The article by Solomon et al. CD25-Treg-depleting antibodies preserving IL-2 signaling on effector T cells enhance effector activation and antitumor immunity is published in the journal Nature Cancer – VM.
It is known from previous studies that Treg cells are often found in large quantities in tumors and probably prevent other immune cells from attacking cancerous ones. A distinctive feature of Treg cells is the CD25 protein, which is present in large quantities on their surface.
Previously, scientists have already used drugs to target CD25 to weaken the inhibitory mechanisms, but none of them has shown the necessary effectiveness. Now scientists have found out the reason for these failures.
Targeting CD25 was absolutely the right approach, the scientists were convinced, however, as it turned out, in order to achieve the effect, it was necessary to influence another part of the protein. Previous strategies, in addition to affecting CD25, also unintentionally affected cancer-killing effector T cells, reducing the effectiveness of treatment.
Given the results, the scientists created an antibody to target another part of CD25.
A powerful effect of the therapy was observed in several models of cancer in mice. At the same time, some types of tumors showed almost 100% response with a single injection of the drug.
"The drug not only eliminates regulatory immune cells that weaken the response to the tumor, but also activates cancer-attacking cells. This combined approach opens up new possibilities for attacking the tumor and its microenvironment, since it blocks its defense mechanisms," explained Sergio Quesada, co–author of the study.
Currently, experimental therapy is being tested in the pilot phase of clinical trials involving patients with various types of late-stage tumors.
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