Details

Autor(en) / Beteiligte

• DEN BOER, Annemieke Th
• VAN MIERLO, Geertje J. D
• FRANSEN, Marieke F
• MELIEF, Cornelis J. M
• OFFRINGA, Rienk
• TOES, René E. M

Titel

CD4+ T cells are able to promote tumor growth through inhibition of tumor-specific CD8+ T-cell responses in tumor-bearing hosts

Ist Teil von

• Cancer research (Chicago, Ill.), 2005-08, Vol.65 (15), p.6984-6989

Ort / Verlag

Philadelphia, PA: American Association for Cancer Research

Erscheinungsjahr

2005

Quelle

MEDLINE

Beschreibungen/Notizen

• Modulation of the immune response by established tumors may contribute to the limited success of therapeutic vaccination for the treatment of cancer compared with vaccination in a preventive setting. We analyzed the contribution of the CD4+ T-cell population to the induction or suppression of tumor-specific CD8+ T cells in a tumor model in which eradication of tumors crucially depends on CD8+ T cell-mediated immunity. Vaccine-mediated induction of protective antitumor immunity in the preventive setting (i.e., before tumor challenge) was CD4+ T cell dependent because depletion of this T-cell subset prevented CD8+ T-cell induction. In contrast, depletion of CD4+ cells in mice bearing established E1A+ tumors empowered the mice to raise strong CD8+ T-cell immunity capable of tumor eradication without the need for tumor-specific vaccination. Spontaneous eradication of tumors, which had initially grown out, was similarly observed in MHC class II-deficient mice, supporting the notion that the tumor-bearing mice harbor a class II MHC-restricted CD4+ T-cell subset capable of suppressing a tumor-specific CD8+ T-cell immune response. The deleterious effects of the presence of CD4+ T cells in tumor-bearing hosts could be overcome by CD40-triggering or injection of CpG. Together these results show that CD4+ T cells with a suppressive activity are rapidly induced following tumor development and that their suppressive effect can be overcome by agents that activate professional antigen-presenting cells. These observations are important for the development of immune interventions aiming at treatment of cancer.