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

molecule consists of two non-covalently associated chains ± a 85-kDa transmembrane
b subunit and a 515-kDa a subunit ± derived by cleavage from a common precursor
protein. Because of its similarity to the low-density lipoprotein receptor
(LDL), CD91 was initially seen as the LDL receptor-related protein (LRP). a2-Macroglobulin
was the first ligand identified for CD91.
Central tolerance
Tolerance towards self-antigen established during the development of T lymphocytes
in the thymus. T lymphocytes that bind with high affinity to MHC/peptide complexes
by thymic antigen-presenting cells die by apoptosis.
Chaperone
Stress protein; highly conserved proteins that non-covalently bind and thereby protect
unfolded or nascent polypeptides to ensure correct folding. They also play a role
as intermediate peptide carriers in antigen processing. There is indirect evidence for a
shuttle function of some chaperones that transport peptides or T lymphocyte epitopes
between cells. Some chaperones such as gp96 exhibit a non-specific immune
stimulatory capacity. Heat shock proteins are a subset of the chaperones.
Chemokine
Chemoattractive polypeptides. Chemokines play a major role in leukocyte trafficking,
and direct lymphocytes, monocytes and other cells of the immune system to sites
of inflammation and active immune responses.
Chimeric receptor
Recombinant receptor molecule composed of domains of different proteins.
Glossary
Coley's toxin
Mixture of killed Gram-positive and Gram-negative bacteria, in some compositions
including Streptococcus and Proteus, that was introduced in 1890 by William B. Coley
to cancer therapy. Coley injected the toxin into sarcomas and observed tumor regression
in many cases. It is not clear what the mechanisms of the clinical effects are. It
has been suggested that lipopolysaccharide might play a role by stimulating polyclonal
B lymphocyte responses or that CpG motifs of the bacterial DNA released from the
toxin might serve as adjuvant to support the induction of antitumor immune responses
by T lymphocytes.
Co-stimulatory molecule
Molecule expressed at the surface of antigen-presenting cells or exchanged between interacting
cells that induce signals in T lymphocytes to support the cellular response
triggered by recognition of cognate MHC/peptide complexes. These signals can be
essential supplements to the primary signals transduced via the T cell receptor to
drive full activation or to direct the type of response, or to suppress activation-induced
cell death of the T lymphocyte. Co-stimulatory signals are essential aspects of
T lymphocyte activation and are dependent on the cooperation of the cells that ex-
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