B cells may play an important role in immunotherapy for melanoma

Reviewed by James Ives, M.Psych. (Editor)Sep 13 2019

Researchers at EMBL's European Bioinformatics Institute and the Medical University of Vienna have found evidence that B cells might play an important role in immunotherapy for melanoma. Currently, immunotherapy is primarily focused on T cells, but the results suggest that B cells could also provide an interesting research avenue.

Immunotherapy is a form of cancer treatment that uses the body's own immune system to recognize and fight the disease. It comes in a variety of forms, including cancer vaccines, targeted antibodies or tumor-infecting viruses. Only some cancer patients currently benefit from this kind of therapy.

In the case of melanoma, which is a particularly aggressive form of skin cancer, established immunotherapies focus on T cells. T cells play an important role in controlling and shaping the immune system and they are able to directly kill cancer cells, while also recruiting other cells into the process.

A recent study published in Nature Communications has shown that, alongside T cells, B cells play a critical role in triggering melanoma-associated inflammation. B cells are a type of white blood cell, which can produce antibodies along with several important messenger molecules. The researchers found that, in the case of melanoma, B cells act almost like a satnav, directing T cells to the tumor via the secretion of such distinct messenger molecules.

Immunotherapy has transformed cancer treatment. It unleashes T cells so they can fight cancer in a more effective way. For the first time, we found that B cells also play an important part in the process and help T cells find the tumor. The role of B cells in immunotherapy is still largely unknown, but it seems they may have more impact than previously thought."

Johannes Griss, Researcher, Medical University of Vienna and EMBL-EBI

During the study, the researchers observed that when B cells were depleted from melanoma patients, the number of T cells and other immune cells dramatically decreased within the tumors as well. In subsequent experiments, the researchers showed that a special subtype of B cells seems to be responsible for guiding T cells and other immune cells to the tumor.

Interestingly, melanoma cells seem to force B cells to develop into this distinct B cell subtype. Most excitingly, this specific B cell subtype also increased the activating effect of current immune therapies on T cells, and higher numbers of this B cell subtype in tumors before therapy predicted that a patient would respond better to subsequent immunotherapy.

"Further research is required to answer questions such as how melanoma cells modify B cells, what mechanism B cells use to support the activation of T cells, and how we can help these B cells to support current immunotherapies in cancer patients," concludes Griss.