Mobilizing the low-avidity T cell repertoire to kill tumors

Semin Cancer Biol. 2007 Aug;17(4):317-29. doi: 10.1016/j.semcancer.2007.06.006. Epub 2007 Jun 23.


Optimally, T cells destroy infected and transformed cells of the host. To be effective the T cell repertoire must have a sufficiently diverse number of T cell receptors (TCRs) to recognize the abundance of foreign and tumor antigens presented by MHC molecules. The T cell repertoire must also not be reactive toward self-antigens on healthy cells to prevent autoimmunity. Unlike antigens derived from pathogens, most tumor-associated antigens (TAA) are also self-antigens. Therefore, central and peripheral tolerance mechanisms delete or inhibit tumor-reactive T cells. Although there are T cells within the peripheral repertoire that recognize TAA, these T cells are not sufficient to prevent growth of clinically relevant tumors. We will discuss how this dysfunction results, in part, from the low functional avidity of T cells for tumor, or antigen presenting cells (APC) displaying TAA. We discuss the limitations of these low-avidity tumor-reactive T cells and review current immunotherapies aimed at enhancing the avidity and antitumor activity of the tumor-specific T cell repertoire.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Autoimmunity
  • Cytotoxicity, Immunologic
  • Epitopes, T-Lymphocyte / immunology*
  • Graft Rejection / immunology*
  • Humans
  • Lymphocyte Activation
  • Neoplasms / immunology*
  • Neoplasms / therapy
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism


  • Epitopes, T-Lymphocyte