QFR 5 Flashcards
●
are excellent antigens because of their:
○
High molecular weight
○
Structural complexity
Protein-based antigens
are inferior antigens because of their
relative simplicity and lack of structural
stability.
Lipids
are poor antigens because of relative
simplicity, molecular flexibility, and their
rapid degradation.
Nucleic acids
the more that your antigens
would
come
from
different
species of certain animals or
plants and they are introduced
to our system, the more that
they are likely to produce an
immune response within our
body
Foreigness
____________ or your own
antigens will not induce an
immune response within your body.
Because
it
will
be
contained
within your body
naturally
Autoantigens
a. the higher resistance an antigen is when
it comes to the different processes
within our body,then there is a chance
that that antigen could become an
immunogen.
b. But the higher the chances that your
antigen would be easily degraded, then
it is more likely that it will not induce an
immune response.
Degradability
a. the higher the molecular weight, the
better the molecule will function as an
antigen.
Molecular weight
a. If a molecule is an effective antigen,
__________________ is mandatory.
b. If a structure is unstable,the molecule
will be a poor antigen.
Structural stability
________________ are poor antigens
because they would not interact with our
immune system
Totally inert molecules
a. the more complex an antigen, the
greater is its effectiveness.
b. Proteins are better antigens compared
to the polymers of carbohydrates, your
polysaccharides, and even the different
polymers of lipids and nucleic acids.
Complexity
substances that are
presented into our
body, which is not
typically there.
Antigen
composed of different
biomolecules like
proteins,
polysaccharides,
lipids, and even
nucleic acids
Antigen
antigens that could
induce an immune
reaction within our
body mostly made up of
proteins and even
polysaccharides
Immunogen
substances that are non-immunogenic
but it can react with the products of a
specific immune response, even with no
antibody formation.
-
low molecular weight of less than
10,000 daltons that could never induce
an
immune
response
when
administered on their own.
-
But if it is coupled to a carrier molecule,
there is a higher chance that these
happens could be considered as an
immunogen.
-
property of antigenicity
Haptens
are derived from your own body or they
are derived from the same individua
Autoantigens
are antigens that are derived from a
different individual of the same species
Alloantigens
these are
antigens that are derived from different
species.
Xenogenic / heteroantigens
antigens that are found in unrelated
plants and animals, which can actually
cross-react with an antibody of another
that had induced the said immune
response or the induction of the
antibody production.
Heterophile antigens
These antigens are not seen by
the developing immune system
and
will
not
induce
self-tolerance
Sequestered
these are antigens that are
characteristic of one tissue or
cell only.
Tissue-specific antigens
do not directly stimulate the
production of Ab without the
help of T-cells
T-dependent
can directly stimulate without
T-cells
T-independent
able
to
elicit
T-lymphocyte
responses
by
circumventing
normal antigen processing and
presentation functions.
Super antigens
Proteins that have the ability to bind to an
invariant region of the class II MHC on an APC
and to crosslink this receptor to a T-cell through
binding to the variable region of the beta-chain
of the T-cell antigen receptor
Super antigens
Proteins produced by the body in
response to an antigen
-
Can react in observable means (e.g.
agglutination, flocculation, precipitation
techniques)
-
Observation of Ag–Ab interactions in
vitro is the main basis of most serologic
reactions
-
Aids in disease dx (hepatitis B, hepatitis
C, HIV)
Antibodies
known to be great opsonins, also
known to activate the complement cascade
IgG and IgM
-
directed against an antigen
within their own.
-
Basis of autoimmune diseases.
Autoantibody
-
produced
because
of
the
introduction of antigens from the
same species.
Alloantibody
produced to one heterophile Ag,
which will cross react with
antibodies to the other
Heterophile Antibody
capable of reacting with many
RBCs
Polyagglutinin
reacts to all reagent cells in an
Ab panels
Panagglutinin
antibodies
can be formed after exposure to
environmental agents that are
similar to red cell antigens, such
as bacteria, dust, or pollen.
-
Sensitization through previous
transfusions,
pregnancy,
or
injections is not necessary
Naturally-occurring
antibodies
formed
from
sensitization
-
Antigens
have
elicited
the
production of antibodies through
an immune response
Immune
In cases of HDN (Hemolytic
Disease of the Newborn), when
the mother who is an Rh- tries
to produce an offspring with an
Rh+ male, the male could pass
on the Rh+ gene to their
offspring. Since the offspring
now has the RhD antigen on the
RBC, once the mother has
given birth, the bleeding will
introduce the RhD antigen to
her blood producing alloanti-D
which
will
remain
in
her
circulation.
Immune
antibody that particulates in
agglutination reaction. IgM and
IgG
Agglutinin
antibody that participates in
agglutination caused by red
cells. IgM and IgG, sometimes
even IgA
Hemagglutinin
antibody that participates in
precipitation reactions
Precipitin
a
substance
such
as
streptolysin O and streptolysin S
produced by most group A
strains
of
streptococci
that
disrupts the membrane integrity
of red blood cells, causing the
release of hemoglobin.
Hemolysin
antibody does not produce any
visible reaction with the antigen
when combined with it, but
blocks
anything
else
from
reacting with its antigen.
Blocking antibody
antibody which can take part
(directly)
in
agglutination
reactions. IgM are known to be
potent agglutinins
Complete antibody
interacts at incubated temp
(37C).
Warm reacting
What Ig is a warm reacting?
IgG
actions observed at 4C to 22C
Cold reacting
What Ig is cold reacting?
IgM
antibody
that
can
cause
irreversible
leakage
of
cell
contents
that
occurs
after
membrane damage
Lysin
antibody that is capable of
enhancing phagocytosis
Opsonin
antibodies against viral surface
antigens, which can bind to the
free virus in the body to prevent
it from being absorbed and
invade cells. Also necessary for
the neutralization of viral toxins.
Neutralizing antibody
Ab that can bind to Mast cells
and
Basophils
causing
an
allergic reaction
Allergic/reaginic antibody
derived from a single
B-cell clone and are
produced as a single
class of
immunoglobulin with
specificity unique to
the antigenic
stimulus.
- more specific in
reaction
Monoclonal
produced as different
classes of
immunoglobulins by
many B-cell clones in
response to an
antigen
- They could be a
just single class of
immunoglobulins or
multiple class of
immunoglobulins
that are produced
by multiple b cells
- more sensitive
Polyclonal
refers to the heavy chain that determine
the Ig class
Isotype
●
Minor variations in the constant region
●
E.g Allotypes occur in the four IgG
subclasses, in one IgA subclass, and in
the kappa light chain.
ALLOTYPES
●
Variations in variable regions
that
could
affect the sensitivity and
specificity of antibodies
●
The amino terminal ends of both L and
H chains contain these regions, which
are essential to the formation of the
antigen-binding site
IDIOTYPE
●
main antibody directed mechanism for
triggering complement activation
●
In the presence of IgM &IgG the
classical
complement
pathway
is
started.
●
What mediates the start of the classical
complement cascade would actually be
the presence of an antibody
on a
certain cell . (eg. bacterial cell, rbc)
Classical
●
can destroy pathogens without an
antibody.
●
It acts as an early defense against
pathogens
Alternate
What is the other name of the classical pathway?
properdin pathway
●
represents another means
of
activating
.complement
without
antibody being present.
●
The main player in this pathway is the
presence
of
“mannose”
which
is
carbohydrate that is found commonly in
most of microbial cell walls
Mannose binding-lectin
What are the roles of the complement
system in
a. Serologic reactions ?
It is necessary that sometimes complements are
inactivated in order to not see their interaction
which can heighten the sensitivity
of the test
result
What are the roles of the complement
system in
b. Immune response?
omplement
proteins
are
mainly
involved in the lysis of pathogen or in some
cases they are involved in hemolysis where in
the rbc’s are destroyed because of the
attachment of some antibodies on rbc .
More Ab (patient) excess than Ag
remedy: Serum dilution
Prozone
Ag excess, less Ab (Patient) may
lead to false negative
Post zone
there is an equal amount
of antibody and antigen that could cause lattice
formation which will allow us to see if there is an
antibody- antigen interaction.
Zone of equivalence
