CD25, also known as the interleukin-2 receptor α chain (IL-2Rα), is highly expressed on regulatory T cells (Tregs), but relatively lower on effector T cells (Teffs). This makes it a potential target for Treg depletion, which can be used in tumor immunotherapy. However, marketed anti-CD25 antibodies (Basiliximab and Daclizumab) were originally developed as immunosuppressive drugs to prevent graft rejection, because these antibodies can block IL-2 binding to CD25 on Teffs, which in turn destroys the function of Teffs. Recent studies have shown that non-IL-2-blocking anti-CD25 antibodies have displayed exciting antitumor effects. Here, we screened out a non-IL-2-blocking anti-CD25 monoclonal antibody (mAb) 7B7 by hybridoma technology, and confirmed its antitumor activity via depleting Tregs in a CD25 humanized mouse model. Subsequently, we verified that the humanized 7B7, named as h7B7-15S, has comparable activities to 7B7, and that its Treg depletion is further increased when combined with anti-CTLA-4, leading to enhanced remodeling of the tumor immune microenvironment. Moreover, our findings reveal that the Fab form of h7B7-15S has the ability to deplete Tregs, independent of the Fc region. Taken together, our studies expand the application of anti-CD25 in tumor immunotherapy and provide insight into the underlying mechanism.
© 2024 UICC.

Therapies for bladder cancer patients are limited by side effects and failures, highlighting the need for novel targets to improve disease management. Given the emerging evidence highlighting the key role of innate lymphoid cell subsets, especially type 2 innate lymphoid cells (ILC2s), in shaping the tumor microenvironment and immune responses, we investigated the contribution of ILC2s in bladder tumor development. Using the orthotopic murine MB49 bladder tumor model, we found a strong enrichment of ILC2s in the bladder under steady-state conditions, comparable to that in the lung. However, as tumors grew, we observed an increase in ILC1s but no changes in ILC2s. Targeting ILC2s by blocking IL-4/IL-13 signaling pathways, IL-5, or IL-33 receptor, or using IL-33-deficient or ILC2-deficient mice, did not affect mice survival following bladder tumor implantation. Overall, these results suggest that ILC2s do not contribute significantly to bladder tumor development, yet further investigations are required to confirm these results in bladder cancer patients.
Copyright © 2024 Schneider, Domingos-Pereira, Cesson, Polak, Fallon, Zhu, Roth, Nardelli-Haefliger and Derré.

NK/T-cell neoplasms are rare, highly aggressive, and insensitive to chemotherapy. These lymphomas have a poor prognosis, with patients being vulnerable to relapse. Hence, there is a need for alternative treatments. The purpose of this study is to investigate whether anti-PD1 takes effect on NK/T cell lymphoma.
The expression of PD-L1 in NK/T cell lines was investigated by flow cytometry and by Western blot. In vivo, overall survival and median survival time of mice bearing an NK/T cell line tumor was assessed. Tumor-infiltrating T cells and monocyte-derived suppressor cells were evaluated by flow cytometry. Levels of PD-L1 and components of the JAK-STAT pathway were assessed in tumor tissues by immunohistochemistry.
NK/T cell lines had greater expression of PD-L1 than normal peripheral blood human NK cells. In vivo, anti-PD1 treatment improved overall survival and median survival time of mice bearing an NK/T cell line. Furthermore, anti-PD1 treatment increased levels of PD-L1. Cultured tumor-infiltrating lymphocytes from mice treated with anti-PD1 had greater levels of IFN-γ than cultured lymphocytes from untreated animals. Further, levels of JAK2 and STAT1 were greater in mice treated with anti-PD1.
In vivo, anti-PD1 inhibited the progression of an NK/T-cell lymphoma and up-regulated PD-L1 expression. This up-regulation may be through the IFN-γ-associated JAK-STAT pathway.