T cells are immune cells that fight off disease. The most common type of T cell, known as conventional T cells, maintains different functions, including activation of other T cells and killing pathogens. However, there is a less common type of T cell known as unconventional T cells. These cells regulate conventional T cells and often suppress conventional T cell function. How these cells develop and protect the body from infection and disease is unclear. Dr. Dan Pellicci and colleagues from Murdoch Children’s Research Institute and Federation University Australia reported on unconventional T cell development and their role in the immune system in a recent Science Immunology paper.

The researchers found that these unconventional T cells elicit an immune response. The discovery of an anti-pathogen role in these T cells has been unknown previously. Scientists can target these cells to prevent cancer and highly infectious diseases by understanding their role in immunity.

Dr. Pellicci and colleagues gathered samples from the Melbourne Children’s Heart Tissue Bank, where samples from children sixteen years old or younger who had heart surgery were kept. The researchers looked at the T cells from the thymus, a gland that further develops or matures T cells. After the T cells exit the thymus, they are ready to activate and target or kill infecting pathogens. Through T cell isolation, Dr. Pellicci and colleagues were able to determine the role of Unconventional T cells.

Ovarian cancer is the fourth-leading cause of cancer mortality among women and is characterized by late detection, extensive metastasis and poor prognosis.

One reason that treating this disease has been so challenging is that tumors often become resistant to chemotherapies, and generally respond poorly to immunotherapies.

While much of the research on overcoming resistance and efforts to develop new therapies have focused on the cancer cells, it has often ignored the many other cell types within the tumor. Indeed, cancer cells have the ability to reprogram the cells around them to nurture the tumor and help evade the patient’s immune system.

Scientists at the UCLA Jonsson Comprehensive Cancer Center have identified potential new biomarkers that could indicate how someone diagnosed with metastatic melanoma will respond to immunotherapy treatment.

The researchers found when T cells are activated, they release a protein called CXCL13, which helps attract more B cells and T cells to the tumor site. The B cells then show the T cells specific parts of the tumor, which leads to increased activation of the T cells and their ability to fight the cancer. This cooperation between T cells and B cells was associated with improved survival in patients diagnosed with metastatic melanoma who were treated with immunotherapy, but not for those who received targeted therapy (e.g., MEK inhibitors).

These findings could help guide new strategies to improve the effectiveness of melanoma cancer treatments. The research is published in the journal Frontiers in Immunology.