Cancer cells can suppress the host immune response that leads to T-cell exhaustion; checkpoint inhibitors can inhibit such immunosuppression and reactivate the killer T-cells. However, unlike melanoma , lung cancer does not respond effectively to these checkpoint inhibitors. To identify the reason behind this, researchers from the Massachusetts Institute of Technology, USA, implanted tumors in the lungs of mice and studied their immune responses. T-cells from the lung tumors were only partially activated by the dendritic cells.
Regulatory T-cells removed the stimulatory proteins from the dendritic cells’ surface and thus prevented them from activating killer T-cells. Further, researchers also found elevated levels of interferon-gamma in the lung that, in turn, stimulated regulatory T-cells. Interferon-gamma is secreted in response to commensal bacteria living in the lungs. When the mice…
