Ccr8, the CC chemokine receptor 8, is a key molecule involved in the immune system. It plays a role in the trafficking and function of immune cells. The chemokine-receptor interactions mediated by Ccr8 are associated with pathways related to immune cell migration and immune responses, which are of great biological importance in maintaining immune homeostasis and responding to various stimuli [4].

In tumor-related research, studies on mouse models (such as LLC-OVA, MC38) have shown significant findings. Ccr8 is expressed by a sub-population of tumor-infiltrating regulatory T cells (ti-Tregs) in both mouse and human tumors. TCR-mediated Treg triggering in an NF-κB-dependent fashion leads to Ccr8 expression, though it is not essential for the recruitment, activation, or suppressive capacity of these cells. Depletion of Ccr8+ ti-Tregs using ADCC-prone Nb-Fc fusion proteins, anti-CCR8 monoclonal antibodies (mAbs), or Fc-optimized anti-CCR8 antibodies in mouse models elicits antitumor immunity. This depletion is tumor-Treg-restricted, sparing CCR8+ T cells in other tissues. The treatment also synergizes with anti-PD-1 therapy, leading to reduced tumor growth. Moreover, specific removal of clonally expanding Ccr8+ Tregs in tumor tissues can generate potent tumor immunity with long-lasting memory and without severe autoimmunity [1,2,3,5,6].

In conclusion, Ccr8 plays a crucial role in the context of tumor-infiltrating Tregs. Research using mouse models has revealed that targeting Ccr8 for the depletion of ti-Tregs can be an effective and relatively safe strategy in antitumor immunotherapy, providing new insights and potential therapeutic approaches for cancer treatment.