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ISRN Immunology
Volume 2011 (2011), Article ID 497397, 6 pages
http://dx.doi.org/10.5402/2011/497397
Review Article

The Roles of CD4+ T Cells in Tumor Immunity

1Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
2Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei 122, Taiwan
3Department of Medical Research, National Taiwan University Hospital, Taipei 100, Taiwan

Received 8 August 2011; Accepted 20 September 2011

Academic Editors: B. Favier and B. Sawitzki

Copyright © 2011 Yo-Ping Lai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Activation of CD8+ cytotoxic T cells has long been regarded as a major antitumor mechanism of the immune system. Emerging evidence suggests that CD4+ T cells are required for the generation and maintenance of effective CD8+ cytotoxic and memory T cells, a phenomenon known as CD4+ T-cell help. CD4+ T-cell help facilitates the optimal expansion, trafficking, and effector function of CD8+ T cells, thereby enhancing tumor destruction. In addition, a specialized subset of CD4+ T cells, CD4+CD25+ regulatory T cells (TRegs), effectively hampers anti-tumor immune responses, which has been proposed to be one of the major tumor immune evasion mechanisms. Here, we review recent advances in deciphering how anti-tumor immune responses are orchestrated by CD4+ T cells. We will also discuss the immunotherapeutic potential of CD4+ T-cell manipulation in anti-tumor immune response.