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Zinkernagel, Rolf (1944–) and Doherty, Peter (1944–) 761 zymosan
Zinkernagel, Rolf (1944–) and Doherty, Peter (1944–)
Recipients of the 1996 Nobel Prize for Physiology or
Medicine for demonstration of MHC restriction. In an
investigation of how T lymphocytes protect mice against
lymphocytic choriomeningitis virus (LCMV) infection,
they found that T cells from mice infected by the virus
killed only infected target cells expressing the same major
histocompatibility complex (MHC) class I antigens but not
those expressing a different MHC allele. They found that
murine cytotoxic T cells (CTL) would lyse only virusinfected
target cells if the effector and target cells were H-2
compatible. This significant finding had broad implications,
demonstrating that T cells recognize a virus only in conjunction
with MHC molecules and not directly.
Hans Zinsser.
Zinsser, Hans (1878–1940)
A leading American bacteriologist and immunologist and
educator at Columbia, Stanford, and Harvard. His work in
immunology involved hypsersensitivity, plague immunology,
formulation of the unitarian theory of antibodies, and
demonstration of differences between tuberculin and anaphylactic
hypersensitivity. His famous text, Microbiology
(with Hiss, 1911), has been through two dozen editions since
its first appearance.
zippering
A mechanism in phagocytosis in which the phagocyte
membrane covers a particle by a progressive adhesive
interaction. Evidence in support of this process comes from
experiments in which capped B cells are only partially
internalized, whereas those coated uniformly with anti-IgG
opsonizing antibody are engulfed fully.
zirconium granuloma
A tissue reaction in axillary regions of subjects who use
solid antiperspirants containing zirconium. The granuloma
develops as a consequence of sensitization to zirconium.
zonal centrifugation
The separation of molecules according to size based on
molecular mass and centrifugation time.
zone electrophoresis
The separation of proteins on cellulose acetate (or on paper)
based upon charge when an electric current is passed
through the gel.
zone of antibody excess
The part of the precipitin reaction curve that depicts the
sparse immune complexes that may form when the number
of antibody-combining sites is greater than the number of
antigenic epitopes.
zone of antigen excess
That part of the precipitin reaction curve that depicts the
sparse immune complexes that form little or no precipitate
when the number of antigenic epitopes is greater than the
number of antibody-combining sites.
zone of equivalence
That point in a precipitin antigen–antibody reaction in vitro
at which the ratio of antigen to antibody is equivalent, i.e.,
the numbers of antigenic epitopes and antibody-combining
sites are approximately equal. The supernatant contains
neither free antigen nor antibody. All molecules of both
compounds have reacted to produce antigen–antibody
precipitate. When a similar reaction occurs in vivo, immune
complexes are deposited in the microvasculature and serum
sickness develops.
zoonosis
Cross-species infection; an animal disease transmissible
to humans.
zygosity
Characterization of heredity traits in terms of gene pairing
in a zygote from which an individual develops.
zymogen
The inactive state in which an enzyme may be synthesized.
Proteolytic cleavage of the zymogen may lead to active
enzyme formation.
zymosan
A complex polysaccharide derived from dried cell walls of
the Saccharomyces cerevisiae yeast that activates the alternative
complement pathway. It binds to C3b and is useful in
investigations of opsonic phagocytosis.
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