Untitled - D Ank Unlimited

afferent lymphatic vessels 24 agar gel
afferent lymphatic vessels
The channels that transport lymph, which may contain
antigens draining from connective tissue or from sites of
infection in many anatomical locations, to the lymph nodes.
affinity
The strength of binding between antigen and antibody molecules.
It increases along with linkage stability. The affinity
constant reflects the strength of binding. The paratope of an
antibody molecule views the epitope as a three-dimensional
structure. Affinity (K A) is a thermodynamic parameter that
quantifies the strength of the association between antigen and
antibody molecules in solution. It applies to a single species
of antibody-combining sites interacting with a single species
of antigen-binding sites. Affinity describes the strength of
binding between a single binding site of an antibody molecule
and its ligand or antigen. The dissociation constant (K d)
represents the affinity of molecule A for ligand B. This is the
concentration of B required to occupy the combining sites
of half the A molecules in solution. A smaller K d signifies a
stronger or higher affinity interaction, and a lower concentration
of ligand is requisite to bind with the sites.
affinity chromatography
A method to isolate antigen or antibody based upon
antigen–antibody binding. Antibody molecules fixed to a
solid support such as plastic or agarose beads in a column,
constituting the solid phase, may capture antigen molecules
in solution passed over the column. Subsequent elution of
the antigen is then accomplished with acetate buffer at pH
3.0 or diethylamine at pH 11.5.
affinity constant
Determination of the equilibrium constant by applying the
law of mass action to the interaction of an epitope or hapten
with its homologous antibody. The lack of covalent bonds
between the interacting antigen and antibody permits a
reversible reaction.
affinity labeling
A method to label the binding sites of proteins by virtue of a
ligand analog to which a chemically reactive or photoreactive
group has been attached. The latter can bind covalently with
a suitably oriented amino acid in the binding site. A labeling
reagent of this type is comprised of a biologically active substance
that forms a reversible complex with a particular protein
and a properly positioned chemically or photochemically
reactive leaving group. During incubation, the affinity label
reacts with its protein counterpart, leading to the production
of an irreversible protein–ligand complex. The first affinity
labeling studies of antibodies employed diazonium labeling
reagents attached to a benzene arsonate hapten.
IgG2
Affinity maturation.
affinity maturation
The sustained increase in the affinity of antibodies for
an antigen with time following immunization. The genes
encoding the antibody variable regions undergo somatic
hypermutation with the selection of B lymphocytes whose
receptors express high affinity for the antigen. The immunoglobulin
G (IgG) antibodies that form following the early,
heterogeneous IgM response manifest greater specificity
and less heterogeneity than do the IgM molecules.
African swine fever (ASF)
A very contagious acute hemorrhagic disease of pigs that is
induced by a large icosahedral DNA virus that produces a
broad range of clinical signs. Protective immunity has been
induced in vivo but it is now accompanied by the development
of neutralizing antibodies. No vaccine is available.
Patient
+
Control
IgG, IgA and IgM
Missing in patient’s
serum
IgA
Immunoelectrophoresis
Agammaglobulinemia.
IgM
agammaglobulinemia
Refer to hypogammaglobulinemia. Agammaglobulinemia
was used in earlier years before the development of methods
sufficiently sensitive to detect relatively small quantities
of gamma globulin in the blood. Congenital defects in B
cell signaling may lead to one of several primary immunodeficiencies
characterized by lack of antibodies. Primary
agammaglobulinemia was attributed to defective immunoglobulin
formation, whereas secondary agammaglobulinemia
referred to immunoglobulin depletion, as in losses due
to inflammatory bowel disease or through the skin in burn
cases.
agar gel
A semisolid substance prepared from seaweed agar that
was widely used in the past in bacteriology, and is used
in immunology for diffusion of antigen and antibody in
Ouchterlony-type techniques, electrophoresis, immunoelectrophoresis,
and related methods.
–
IgG