Page 68 - Academic Press Encyclopedia of Physical Science and Technology 3rd Molecular Biology

P1: GSS/GLE P2: GPJ Final Pages Qu: 00, 00, 00, 00
Encyclopedia of Physical Science and Technology EN007I-331 July 3, 2001 18:42

Immunology—Autoimmunity

K. Michael Pollard
Eng M. Tan
Scripps Research Institute

I. Autoimmunity and Autoantibodies
II. Detection of Autoantibodies and Autoantigens
III. Perspectives

GLOSSARY whether or not to respond to a suspected challenge. Con-
siderable debate has occurred regarding the definition of
Antibody A protein product of a specific type of lym- self and non-self, with both “infection” and “danger” be-
phoid cell (B cell) which combines with a specific ing suggested as possible discriminators. Irrespective of
molecular target, called an antigen. the final outcome of these discussions, it is clear that idio-
Antigen A substance, usually protein, that combines with pathic autoimmunity constitutes a significant disruption in
an antibody. the mechanisms that regulate the immune systems’ abil-
Autoantigen A constituent of the body that is recognized ity to discriminate at the molecular level. Autoimmunity
by its immune system. An antibody that recognizes an can lead to devastating diseases such as systemic lupus
autoantigen is called an autoantibody. erythematosus (SLE) and insulin-dependent diabetes mel-
Chromophore A chemical group capable of selective litus (IDDM). These two clinical syndromes reflect the
light absorption resulting in the coloration of certain two major types of autoimmunity. SLE is representative
organic compounds. of multisystem autoimmunity, in which disease processes
Neoantigen A new or different antigen. may involve a number of organs of the body. IDDM is il-
lustrative of organ-specific autoimmunity, which is more
restrictive, targeting perhaps a single organ such as the
IN NORMAL circumstances a healthy immune system is pancreas. Advances in our understanding of the relation-
tolerant of the tissue constituents of the host but intolerant ships between autoimmune diseases and the autoantibod-
of nonhost (or “nonself ”) matter such as invading viruses, ies and autoantigens that characterize them have come
bacteria, or other pathogens. In autoimmunity the immune about through the use of an ever-evolving armamentarium
system mounts responses against tissue constituents of the of techniques based in part on the physical sciences. This
host organism. This response is most commonly referred chapter is an attempt to describe the history, principles,
to as recognition of “self,” as opposed to “nonself.” The and methodology of those techniques that have proven
self/nonself paradigm is argued by many to be the ba- the most useful in the characterization of autoantibod-
sis for understanding how the immune system determines ies and autoantigens in both basic and applied research

679