There are multiple types of immune cells in the body which respond to disease and infection. One population of cells includes T cells. T cells are responsible for the killing of infectious pathogens that have entered the body. Most therapies in the last decade have focused on T cells to combat disease, including cancer. However, other cells play a critical role in the immune system. B cells are one cell subset that impact the body’s defense against disease. They have three distinct responsibilities:
(1) B cells generate antibodies against disease. Antibodies are proteins which bind to and neutralize pathogens.
(2) B cells can also present antigens or proteins to other cells, such as T cells, to generate an immune response. T cells will bind to the antigen presented by the B cell and become activated and target the infected cells with similar antigens on their surface.
(3) Finally, B cells also release proteins and molecules to elicit an immune response communicating to other cells that there is an intruder or infection in the body. Although, scientists understand B cells play a critical role in immune responses, their role in anti-tumor immunity is still unclear.
A recent study published in Nature by Dr. Vijay K. Kuchroo and others from the Harvard Medical School and Brigham and Women’s Hospital reported that the deletion of a cell surface marker reduces cancer. Kuchroo and colleagues worked with experts in melanoma to understand the role of B cells more definitively. Researchers used computational analysis to identify genes expressed in B cells. This technique is widely accepted in science and this technique was also used in the Human Genome Project, which determined all the genes within human cells. After analysis in both mouse and human samples, Kuchroo and colleagues found the B cell surface marker, TIM-1 to be expressed in melanoma. In addition, a multitude of other receptors were also identified to contribute to B cell immune function in cancer. However, when further investigating TIM-1, it was clear this marker played a critical role in B cell anti-tumor function.
Kuchroo and colleagues demonstrated that the deletion of TIM-1 improved T cell response to cancer and reduced tumor growth. Interestingly, only TIM-1 had to be deleted from B cells to have an effect on immune response to cancer. No other cell surface marker needed to be deleted for the tumors to shrink in size. Therefore, TIM-1 must play a critical role in B cell suppression within the immune system in the context of cancer. Kuchroo and others state that TIM-1 mediates the activation of B cell activation and its ability to target tumor cells. The results of the study indicate that B cells can impact melanoma growth outcome and promote anti-tumor immunity.
Kuchroo and colleagues have improved our knowledge of B cell function in cancer immunity. Additionally, the study demonstrated the effect of TM-1 not only in mice, but in human samples. This finding provides a new target for therapy in melanoma. Overall, this discovery can be used to improve immunotherapies and the longevity of patients.
Study, Nature, Vijay K. Kuchroo, Harvard Medical School, Brigham and Women’s Hospital, Human Genome Project
