Untitled - D Ank Unlimited

Felton phenomenon 270 fetus allograft
to BCG vaccine, but the delayed-type response is less
intense than in other species. The granulomatous reaction
to tuberculosis is essentially the same as in other mammals.
The major histocompatibility complex (MHC) is
designated FLA and is not polymorphic. The FLA system
contains 10 to 20 class I gene loci, only two of which are
expressed. They manifest five class II gene loci, only three
of which are expressed. The lack of MHC polymorphism
renders bone marrow transplantation very successful in this
species. Cats possess all major complement components at
levels equivalent to those in other mammals. The principal
target organ for anaphylaxsis in the cat is the lung, where
serotonin released from mast cells is the principal mediator.
Flea bite dermatitis is the most frequent allergic skin
disease of cats. Feline blood group antigens are designated
A and B. In the United States, 99% of cats belong to group
A and 1% to group B. Spontaneous autoimmune diseases in
cats include hemolytic anemia, hyperthryoidism, thrombocytopenic
purpura, pemphigus vulgaris, pemphigus foliaceous,
myasthenia gravis, systemic lupus erythematosus,
and arthritis. Cats only rarely have immunodeficiencies.
Chediak–Higashi syndrome is the most common congenital
defect in immune function. The leukocytes manifest
large lysosomal granules, but susceptibility to infection is
not increased. Colostral immunoglobulins are not passively
transferred in cats. Secondary immunodeficiencies
are attributable usually to feline leukemia virus (FeLV)
infection, which often induces severe immunodeficiency in
infected animals. Feline immunodeficiency virus (FIV) is a
lentivirus that infects both domestic and wild cats. It leads
to depletion of CD4 + T lymphocytes and resembles human
AIDS. The virus receptor is mediated through fCD9 rather
than fCD4. There is polyclonal stimulation of B cells and
of fCD8 + T cells. The disease terminates in an AIDS-like
condition. Cats also develop plasmacytomas, although they
are not common.
Felton phenomenon
Specific immunologic unresponsiveness or paralysis
induced by the inoculation of relatively large quantities of
pneumococcal polysaccharide into mice.
Felty’s syndrome
A type of rheumatoid arthritis in which patients develop
profound leukopenia and splenomegaly.
feral mouse
A mouse that returns to the wild from its former commensal
existence.
Fernandez reaction
An early (24- to 48-hour) tuberculin-like delayed-type
hypersensitivity reaction to lepromin observed in tuberculoid
leprosy; a skin test for leprosy.
ferritin
An iron-containing protein that is electron dense and serves
as a source of stored iron until it is needed for the synthesis
of hemoglobulin. It is an excellent antigen and is found in
abundant quantities in horse spleen. Ferritin’s electrondense
quality makes it useful for labeling antibodies or for
identifying and localizing antigens in electron microscopic
preparations.
ferritin labeling
The conjugation of ferritin to antibody molecules to render
them visible in histiologic or cytologic specimens observed
by electron microscopy. Antibodies may be labeled with
Red
blood
cell
Ferritin-labeled
antigen
Receptor site
Ferritin labeling.
Visible on EM
Not visible on EM
ferritin by use of a crosslinking reagent such as toluene-2,4diisocyanate.
The ferritin-labeled antibody may be reacted
directly with the specimen, or ferritin-labeled antiimmunoglobulin
may be used to react with unlabeled specific
antibody attached to the target tissue antigen.
fertilizin
A glycoprotein present as a jelly-like substance surrounding
sea urchin eggs. It behaves as an antigen-like substance
from the standpoint of valence. Sperm, which contain
proteinaceous antifertilizin, agglutinate into clumps when
combined with soluble fertilizin, which is dissolved from
eggs by acidified seawater.
fetal antigen
A fetal or oncofetal antigen expressed as a normal constituent
of embryos and not in adult tissues. It is re-expressed in
neoplasms of adult tissues, apparently as a result of derepression
of the gene responsible for its formation.
fetal–maternal tolerance
Among mammals, a mother’s tolerance for her fetus that
expresses allogeneic paternal MHC molecules. A fetus
implanted into the uterus represents a tissue graft that
avoids rejection. Its survival is facilitated by immune privilege
and other factors.
fetal thymic organ culture (FTC)
The culture in vitro of thymic tissue excised from a fetal
mouse. The thymus in culture retains the capacity to facilitate
T lymphocyte development.
fetus allograft
Success of the haplo-nonidentical fetus as an allograft was
suggested in the 1950s by Medawar, Brent, and Billingham
to rely on four possibilities: (1) the conceptus might not
be immunogenic, (2) pregnancy might alter the immune
response, (3) the uterus might be an immunologically privileged
site, and (4) the placenta might represent an effective
immunological barrier between mother and fetus. Further
studies have shown that transplantation privilege afforded
the fetal–placental unit in pregnancy depends on intrauterine
mechanisms. The pregnant uterus has been shown not to be
an immunologically privileged site. Pregnancies usually are
successful in maternal hosts with high levels of pre-existing
alloimmunity. The temporary status has focused on specialized
features of fetal trophoblastic cells that facilitate transplantation
protection. Fetal trophoblast protects itself from
maternal cytotoxic attack by failing to express on placental