Systemic anti-CD25 monoclonal antibody administration safely enhances immunity in murine glioma without eliminating regulatory T cells.

Peter E. Fecci, Alison E. Sweeney, Peter M. Grossi, Smita K. Nair, Christopher A. Learn, Duane A. Mitchell, Xiuyu Cui, Thomas J. Cummings, Darell D. Bigner, Eli Gilboa, John H. Sampson

Research output: Contribution to journalArticle

112 Scopus citations

Abstract

PURPOSE: Elevated proportions of regulatory T cells (T(reg)) are present in patients with a variety of cancers, including malignant glioma, yet recapitulative murine models are wanting. We therefore examined T(regs) in mice bearing malignant glioma and evaluated anti-CD25 as an immunotherapeutic adjunct. EXPERIMENTAL DESIGN: CD4+CD25+Foxp3+GITR+ T(regs) were quantified in the peripheral blood, spleens, cervical lymph nodes, and bone marrow of mice bearing malignant glioma. The capacities for systemic anti-CD25 therapy to deplete T(regs), enhance lymphocyte function, and generate antiglioma CTL responses were assessed. Lastly, survival and experimental allergic encephalitis risks were evaluated when anti-CD25 was combined with a dendritic cell-based immunization targeting shared tumor and central nervous system antigens. RESULTS: Similar to patients with malignant glioma, glioma-bearing mice show a CD4 lymphopenia. Additionally, CD4+CD25+Foxp3+GITR+ T(regs) represent an increased fraction of the remaining peripheral blood CD4+ T cells, despite themselves being reduced in number. Similar trends are observed in cervical lymph node and spleen, but not in bone marrow. Systemic anti-CD25 administration hinders detection of CD25+ cells but fails to completely eliminate T(regs), reducing their number only moderately, yet eliminating their suppressive function. This elimination of T(reg) function permits enhanced lymphocyte proliferative and IFN-gamma responses and up to 80% specific lysis of glioma cell targets in vitro. When combined with dendritic cell immunization, anti-CD25 elicits tumor rejection in 100% of challenged mice without precipitating experimental allergic encephalitis. CONCLUSIONS: Systemic anti-CD25 administration does not entirely eliminate T(regs) but does prevent T(reg) function. This leads to safe enhancement of tumor immunity in a murine glioma model that recapitulates the tumor-induced changes to the CD4 and T(reg) compartments seen in patients with malignant glioma.

Original languageEnglish (US)
Pages (from-to)4294-4305
Number of pages12
JournalClinical cancer research : an official journal of the American Association for Cancer Research
Volume12
Issue number14 Pt 1
DOIs
StatePublished - Jul 15 2006

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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