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autoimmune uveoretinitis 88 avian immunity
autoimmune uveoretinitis
An ocular inflammation and the leading cause of visual
impairment in a significant segment of the population.
T cell autoimmunity is postulated to play a significant role
in the pathogenesis of at least some of these conditions. An
organ-specific inflammatory autoimmune disease of the
neural retina of the eye with Th1 lymphocyte and monocyte
infiltration across the blood–retina barrier. Autoantibodies
against retinal antigens may also be detected.
autoimmunity
Immune reactivity involving either antibody-mediated
(humoral) or cell-mediated limbs of the immune response
against the body’s own (self) constituents (i.e., autoantigens).
May induce autoimmune disease if there has
been a breach in peripheral tolerance mechanisms. When
autoantibodies or autoreactive T lymphocytes interact
with self epitopes, tissue injury may occur; for example,
in rheumatic fever, the autoimmune reactivity against
heart muscle sarcolemmal membranes occurs as a result
of crossreactivity with antibodies against streptococcal
antigens (molecular mimicry). Thus, the immune response
can be a two-edged sword, producing beneficial (protective)
effects while also leading to severe injury to host
tissues. Reactions of this deleterious nature are referred to
as hypersensitivity reactions that are subgrouped into four
types.
autoinflammatory syndromes
Primary immunodeficiencies marked by episodes of severe
local inflammation and extended periods of fever without
any clear pathogenic etiology.
autologous
Derived from self. The adjective describes grafts or
antigens taken from and returned to the same subject from
which they were derived.
autologous bone marrow transplantation (ABMT)
A bone marrow transplant by a donor who may later
become the recipient of the same transplant. Leukemia
patients in remission may donate marrow that can be
readministered to them after a relapse. Leukemic cells are
removed from the bone marrow, which is cryopreserved
until needed. Prior to reinfusion of the bone marrow,
the patient receives supralethal chemoradiotherapy. This
therapy has improved considerably the survival rates of
some leukemia patients.
autologous graft
The donation of tissue such as skin or bone marrow by an
individual who will subsequently receive it either at a different
anatomical site, as in skin autografts for burns, or at a
later date, as in autologous bone marrow transplants.
autologous graft-vs.-host disease
A condition that may occur following autologous bone
marrow transplantation in cyclosporine-A-treated patients.
Autologous graft-vs.-host disease is associated with the
emergence of autoreactive T cells recognizing self major
histocompatibility complex (MHC) class II antigens and the
elimination of a T cell-dependent peripheral autoregulatory
mechanism. The induction of autograft-vs.-host disease may
be of benefit to autologous bone marrow transplant patients
by providing a graft-vs.-tumor effect.
autolymphocyte therapy (ALT)
An unconfirmed immunotherapeutic treatment for metastatic
renal carcinoma. Leukocytes from a patient are
isolated and activated with monoclonal antibodies to
induce the leukocytes to synthesize and secrete cytokines.
Cytokines produced in the supernatant are combined with
a sample of the patient’s own lymphocytes and reinjected.
Preliminary reports claim success, but these have not been
confirmed.
autoradiography
A method employed to localize radioisotopes in tissues or
cells from experimental animals injected with radiolabeled
substances. The radioisotopes serve as probes bound to specific
DNA or RNA segments. Radioactivity is detected by
placing the x-ray or photographic emulsion into contact with
the tissue sections or nylon/nitrocellulose membranes in
which they are localized to record sites of radioactivity. The
technique permits the detection of radioactive substances
by analytical methods involving electrophoresis, Southern
blotting, and Northern blot hybridization.
autoreactive T lymphocytes
Autoreactive T cells in selected diseases may represent
a failure of normal regulation; when present in a normal
healthy individual, they may be necessary aspects of the
immune system. Autoreactive T cells develop from mature
antigen-dependent precursor cells that have changed physiologically
in a manner that restores their thymic-selected ability
to respond to self. Any mechanism that returns T cells to
a resting state would halt autoreactive expansion until stimulation
is induced once again by a specific foreign antigen.
Chronic stimulation in the presence of continuous expression
of high levels of major histocompatibility complex (MHC)
class II molecules together with abnormal immune regulation
can lead to severe and persistent inflammation.
autoreactivity
An immune response against self antigens.
autosensitization
Reactivity against one’s own antigens (i.e., autoantigens)
that occurs in autoimmunity and autoimmune disease.
autosomal, autosomes
Nonsex (nonX and nonY) chromosomes.
Avery, Oswald T.
Investigator at the Rockefeller Institute for Medical
Research, New York in the 1940s. Together with MacLeod
and McCarty, he identified DNA as the transforming principle
in a landmark paper in the Journal of Experimental
Medicine titled “Studies on the chemical nature of the
substance inducing transformation of pneumococcal types.”
avian immunity
Although turkeys, ducks, pigeons, and Japanese quail have
been investigated, the domestic chicken is the principal representative
of this biological group. There is much similarity
between the avian and the mammalian immune systems,
especially with respect to lymphoid organ structure, the
generation of antibody variability, and the arrangements
of immunoglobulin and major histocompatibility complex
(MHC) genes. More than a dozen highly inbred chicken
strains have been used in research. Chickens are usually
excellent antibody producers. Their immune responses
develop early. They form immunoglobulin M (IgM) prior to
IgG and develop poor affinity maturation, reflecting the lack
of extensive generation of antibody variability in peripheral
tissues. Monoclonal antibodies are difficult to prepare from
chicken cells. B lymphoid cell development takes place in
a distinct primary lymphoid organ, the bursa of Fabricius.