Immune cells fight tumors by damaging their blood supply
The immune system can attack cancer in a way researchers long overlooked: by damaging the blood vessels that feed a tumor. That is what a new study published in Science reports.
CD4+ T cells are a type of immune cell best known as ‘helper cells,’ supporting other immune cells in attacking pathogens or cancer. But this new research shows they can also tackle tumors directly. They do so not by killing cancer cells outright, but by damaging the blood vessels the tumor relies on for nutrients.
The researchers identified two signaling molecules as key players: IL-3 and TNF. These substances are secreted by CD4+ T cells and damage the inner lining of blood vessels near the tumor, starving cancer cells of oxygen and nutrients. The study was published in Science.
A new mechanism for cancer therapy
This mechanism had not previously been described as an independent strategy of CD4+ T cells. It opens the door to new forms of immunotherapy, treatments that use the body’s own immune system against cancer. Current immunotherapies focus mainly on CD8+ T cells, the so-called ‘killer cells.’ This research suggests CD4+ T cells may play a complementary role that has been underutilized.
From a longevity perspective, this is relevant because cancer susceptibility rises sharply with age. The immune system weakens over time, reducing its ability to detect and suppress cancer cells. Understanding how CD4+ T cells can constrain tumors may support the development of therapies that maintain this immune function later in life.
What remains unclear
The study is largely based on laboratory and animal models. Whether the IL-3/TNF mechanism works as effectively in humans, and whether it can be activated safely without harming healthy tissue, requires further research. The findings are a promising first step, but clinical applications remain distant.