Certain Immune Cells May Hinder the Effectiveness of Cancer Immunotherapy

A Karolinska Institutet study shows neutrophils can hinder the effectiveness of cancer immunotherapy by shaping the tumor microenvironment. The researchers studied two murine cancer models, melanoma and breast carcinoma, comparing outcomes in mice completely lacking neutrophils with those maintaining normal neutrophil populations. The absence of neutrophils enhanced the efficacy of multiple immunotherapies, with greater tumor reduction and increased infiltration and activation of cytotoxic T lymphocytes (CTLs). Additionally, neutrophils exposed to immunotherapy began expressing PD-L1, a checkpoint molecule that can suppress T cell activity, a response driven by interferon-gamma. Blocking PD-L1 or the IFN-γ receptor on neutrophils restored immunotherapy efficacy.