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instructive theory of antibody formation 393 insulin receptor antibodies
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Antigen
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Antibody
Instructive theory of antibody formation.
when it was shown that the specificity of antibodies in all
cases is due to the particular arrangement of their primary
amino acid sequences. De novo synthesis template theories
that recognized the necessity for antibodies to be synthesized
by amino acids in the proper and predetermined order
still had to contend with the serious objection that proteins
cannot serve as informational models for the synthesis of
proteins. Instructive theories were abandoned when immunologic
tolerance was demonstrated and antigen was shown
not to be necessary for antibody synthesis. The template
theories never explained the anamnestic (memory) immune
response. Antibody specificity depends on the variable
region amino acid sequence, especially the complementarity-determining
or hypervariable regions.
instructive theory of antibody formation
Refer to instructive theory.
insulin-dependent (type I) diabetes mellitus (IDDM)
Juvenile-onset diabetes caused by diminished capacity to
produce insulin. Genetic factors play a major role, as the
disease is more common in HLA-DR3- and HLA-DR4positive
individuals. Significant autoimmune features
include immunoglobulin G (IgG) autoantibodies against
glucose transport proteins and anticytoplasmic and antimembrane
antibodies directed to antigens in the pancreatic
islets of Langerhans; β cells are destroyed, and the
pancreatic islets become infiltrated by T lymphocytes and
monocytes in the initial period of the disease. Experimental
models of IDDM include the NOD mouse and the BB rat.
insulin-like growth factors (IGFs)
Insulin-like growth factors consist of prohormones IGF-I
and IGF-II with M r of 9 and 14 K, respectively. IGF-I is a
7.6-kDa side chain polypeptide hormone that resembles
proinsulin structurally. It is formed by the liver and by fibroblasts.
IGF-I is the sole effector of growth hormone activity
and is a primary growth regulator that is age-dependent.
It is expressed in juvenile life but declines after puberty.
Circulating IGFs are not free in the plasma but are associated
with binding proteins that may have the function of limiting
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Glucose
GLUT-2
Initial Events in Type I DM
β CELL
GK
Glu
G-6-P
GAD
Insulin
GABA
the bioavailability of circulating IGFs that may be a means
of controlling growth factor activity. IGF-II is present mainly
in various tissues during the embryonic and fetal stages of
mammalian development. It is also present in the circulating
plasma in association with binding proteins, reaching its
highest level in the fetal circulation and declining following
birth. IGF-II is important for growth of the entire organism.
insulin-like growth factor-II (IGF-II)
A fetal growth factor expressed at high levels in many tissues
during fetal and early postnatal development but only
in the central nervous system thereafter.
insulin receptor antibodies
Antibodies that lead to insulin resistance and may also be
associated with acanthosis nigricans and manifestations
of autoimmune disease. Insulin receptor antibodies may
lead to hypoglycemia possibly associated with autoimmune
disease and Hodgkin disease. Selected patients with
Insulin
MACROPHAGE T LYMPHOCYTE
Phagosoma
Lysosome
CLASS II MHC
IL-1
Diabetes mellitus type I.
CD4
TCR
CD3
IL-1R
Insulin-dependent (type I) diabetes mellitus (IDDM). (Immunofluorescence
of renal glomerulus.)
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