The reputed Cancer Immunology Research journal published a study from Tel Aviv University researchers experimenting with eosinophils to eliminate malignant colon cancer cells. Accounting for 1 to 3 percent of all white blood cells, their antitumorigenic effect could represent an important new weapon against a variety of malignancies.
“Eosinophils are white blood cells that secrete powerfully destructive proteins”, explained lead investigator Prof. Ariel Munitz, from the Department of Microbiology and Clinical Immunology. “They may have played an evolutionary role in combatting parasites. But now that most people, particularly in the West, enjoy good hygiene and few parasites, the eosinophils have become destructive agents, causing allergies and asthma”.
Since eosinophils are part of the immune system and have been known to combat infections, the team wondered about the possibility of activating them to attack cancer cells. The largest concentration of eosinophils is situated in the digestive system, so initial tests focused on colon cancer. They analyzed samples of tumors from 275 patients to determine the number of eosinophils compared with the stage and severity of the disease.
“We found that the higher the number of eosinophils in the tumor, the less severe the disease, which represents a clear correlation“, noted Prof. Munitz. “We identified that the cancerous environment attracts these cells, which infiltrate the tumors and flourish there for a long time”.
The next step was to confirm their hypothesis in laboratory conditions using animal models of colorectal cancer. They discovered that eosinophils displayed potent anti-tumor activities and could directly kill tumor cells.
“We also found that when eosinophils were activated by a protein called IFN-gamma, they induced an even greater tumor-killing response,” added TAU professor. “Following various extensive analyses, we concluded that eosinophils have unique and distinct activities in comparison with other cells present in the tumor. For example, eosinophils can kill tumors independently of known tumor-fighting cytotoxic T cells“.
These findings could open new therapeutic paths for addressing cancer care, either by harnessing eosinophils for an anti-tumor response or by combining them with other approaches, like cytotoxic T cells.
“We have discovered a new target for immunotherapy for cancer patients — the eosinophils“, concluded Prof. Munitz. “We hope that our research will serve as a foundation for drug development in a number of different approaches“.
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