Cancer Immune Therapy Edited by G. Stuhler and P. Walden ...

tumors recruit to avoid triggering what are effectively autoimmune responses. However,
before any of us can hope to appreciate the interests of others, we will all have
to start by understanding our self.
Acknowledgments
I thank Toni Higgins for expert secretarial assistance. R. V. is supported by the Mayo
Foundation and some of the ideas for this review came from support from NIH
grant RO1 CA85931.
Appendix: Glossary
Appendix: Glossary
Adjuvants. Materials (often derived from microorganisms) which stimulate the innate
immune system. This stimulates the production of inflammatory cytokines,
and leads to recruitment and activation of APCs by inducing expression of MHC
class II molecules as well as co-stimulatory proteins.
Antigen/epitope. Any protein expressed in a cell. Antigens are continually proteolytically
processed within the cell and presented as small fragments (8±13 amino acids)
± known as epitopes ± in the context of MHC class I or II molecules to T cells. Any T
cells which express a TCR with a high enough affinity for any of the epitope/MHC
complexes will recognize cells expressing the parent antigen from which the epitope
was derived.
CD4T cell help. Generation of an effective immune response to an antigen requires
presentation of epitopes of the antigen to both CD8 + T cells and CD4 + T cells. CD4 T
cell activation leads to the secretion of helper cytokines which activate other immune
cells (including the CD8 T cells) important in generating a potent immune response
to the antigen.
Central tolerance. APCs in the thymus display epitopes of self proteins in the context
of MHC molecules to naive T cells. Any T cells which express a TCR with a high enough
binding affinity for any self/MHC complex is induced to die by apoptosis This
thymic deletion of potentially self-reactive T cells helps to induce immunological tolerance
whereby antigen-specific cells can co-exist with antigen expressing cells in the
periphery (see Box 10.1).
Co-stimulatory molecules. A naive T cell will only be fully activated when binding an
epitope/MHC molecule on the surface of an APC if it also receives additional activating
signals. These are provided by binding of co-stimulatory molecules ± such as B7
and OX-40L ± on the surface of the APC to receptors on the T cell surface.
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