UNIT 3 Flashcards
belong to the host
○ Can be a tolerogen since it belongs to the
host
autoantigens
from other members of the host’s
species
alloantigens
from other species
heteroantigens
hetero ags that exist in
unrelated plants or animals but are either identical or closely-related in structure so that ab to one can
cross react w/ ag of the other.
heterophile antigens
antigens that can be tolerated by the
immune system; it could be an autoantigen
(self-antigen)
tolerogen
Substance administered with an immunogen that
increases and hastens the immune response
adjuvants
Ag capable of stimulating the IR
immunogens
Are antigens that can be recognized and should be
reacted by immune system, eliciting a response
immunogens
Generation of immune
response against an immunogen
immunogenecity
All immunogens are antigen; but not all antigens are
immunogen
TRUE
best immunogens
proteins
Present in the pathogen
PAMP
This is the pattern recognized by
PRR and deemed foreign, eliciting
response
PAMP
This recognizes damaged patterns
and considers it foreign therefore
removed from the immune system
DAMP
the ability of the APR to
degrade the antigen to smaller pieces;
smaller pieces are easier to lyse
degradability
antigen still remains present in the APR until
communicated with T Cell (must remain
stable to be detected by T cell pag pinasa ni
APR)
stability
MHC Class I
TC
MHC Class II
TH
CD8+ / All nucleated cell / red
cell
MHC Class 1
APC (dendritic, Macrophage /
Monocyte, B cell)
MHC Class 2
Any cell which utilizes MHC______ communicates with T cytotoxic or T suppressor cells
Class I
but in certain times,
specially _______ there is a chance
for them to use class 1 molecules.
dendritic cells
is the most potent
APC because it effectively uses
both Class II (CD4+ T helper) and
Class I (CD8+ T8 cytotoxic) MHC
DC
small substances that are
non-immunogenic in itself.
Complexed to larger molecule (carriers) to be
immunogenic
HAPTENS
It requires a carrier protein for them to be an
immunogen and be recognized by the immune system
TRUE
most potent APR during
inflammation and can increase up to 100-1000x
CRP
Cutting; breaks down/maps out the effects
of neutrophil (eats and becomes destroyed
(frustrated phagocytosis) → leaves kalat →
_______cleans it
a1 antitrypsin
Should create lysis
○ Attach to the cell surface of the antigen
acting as an opsonin (C4, C1 etc)
complement proteins
Should create lysis
○ Attach to the cell surface of the antigen
acting as an opsonin (C4, C1 etc)
complement proteins
Needed for digestion of cholesterol, Accumulates in the cytoplasm of
the macrophage → lead to
nonfunctional macrophage, hence it should be removed from the cytoplasm by
serum amyloid A
Binds to free hemoglobin (in the form of ferrous)
haptoglobin
Binds to copper
Translates iron so that the ferric state would
bind to the transferrin and then go to the
bone marrow (Ferrous to Ferric)
ceruloplasmin
Antigens that induce tolerance
tolerogens
________are tolerogens; not attacked by your
immune system because they are known to your
immune system
Type A given to Type B
○ To the donor (Type A) - A antigen is a
tolerogen
○ To the recipient (Type B) - A antigen now
becomes an immunogen
BLOOD TYPES
small portion of the antigen is recognized by its
corresponding receptor
epitopes
Recognized both linear and conformational
epitopes present on the surface of an
immunogen
B CELLS
is most effective
in extracellular infection; anything
in the blood/tissues, the B cell
attaches and recognizes it
HUMORAL
Recognized epitope only as a part of the
complex formed with MHC on the surface of
antigen-presenting cells.
■ Only a specific confirmation of the
epitope can be recognized
■ Can only recognize simpler
epitopes = Linear
T CELLS
Binds to antigens
B CELLS
Protein,
polysaccharides,
lipids
b cells
Binds antigenic
peptides bound to
MHC
t cells
Internal linear
peptides produced
by antigen
processing
t cells
Accessible,
sequential or
nonsequential
b cells
Main goal: make the antigen stable (protector); like a
capsule
ADJUVANTS
For it to now melt easily, main use is on
vaccine since external forces can affect the
vaccine
○ Each vaccine has its own
adjuvant
Capable of releasing porphyrin and granzymes
effector t cytotoxic
pro-inflammatory; goal is to kill intracellular
pathogen
th1
Releases Cytokines needed to enhance action against intracellular pathogens
th1
anti-inflammatory; to calm (secretes _____
th2
IL4
IL5
TGF-BETA
IL 10
class switching of
immunoglobulins
IL4 AND IL5
IgM ⟶ IgE
IL4
IgM IgG ⟶ IgA
IL5
anti-inflammatory
cytokine
● Its effect is to calm
overstimulated T-cells.
TGF BETA
TH2
Tells/signals your body to produce
antibody
■ Without this interleukin, your B cell will not function properly
IL10
pro-inflammatory; increased phagocytic
function of the cell (macrophage)
○ Hastens the activity of phagocytes
Needed against extracellular infection such
as fungal infection.
th17
anti-inflammatory
○ Releases IL10 and TGF-Beta
t-regulator
In order for the T cells to recognize an antigen, it
should be processed and broken down into
peptides
bound to the MHC molecules of APCs
peptides
To consider a protein it should contain ______ peptide chains
3
produced by many cells
including antigen presenting cells to cut the
protein into smaller pieces
proteasomes
Only receives the antigen
TCR = CD3
one that recognizes
the MHC molecule at a specific domain
CD4
When CD4 + MHC, it
causes the TCR to receive the antigen:
primary/first signal
Co-stimulatory receptors or molecules.
secondary signals/co-stimulatory
Rule of thumb: both primary and secondary must be
present for an immune response to be present
TRUE
Given that it has antigen, it will activate T
cell and become an effector to do its function; naive T
cell just sleeps
activation
Immunogenicity
co-stimulation
Infections
no co-stimulation
Graft Acceptance
no co-stimulation
Graft rejection
co-stimulation
Self tolerance
Malignancy
No response
no co-stimulation
allergy
co-stimulation
Discovered as a genetic locus that determines
acceptance or rejection of tissue grafts exchanged
between persons
MHC
are polymorphic and its alleles are
co-dominantly expressed
MHC genes
Derives from the research on transplantation that
started in the mid-20th century.
These are studies which provided insights on the rules
governing the acceptance or rejection of tissues
histocompatibility
It is also necessary for control of cellular interaction of
immune cells
Production of certain serum proteins
complex
Are cell surface markers that allow immune cells to
distinguish “self” from “non-self.
Human leukocyte antigens
Markers which can be found within (cytoplasm) and on (trying to present an
antigen to the T cell or it has already
presented the antigen
HLA
HLA antigens are prominent in ______
along with IgD and MHC
mature B
These antigens were first described on white blood
cells (leukocytes) and are coded for by genes in the
MHC located on chromosome
6
products were identified as responsible for
graft rejection
MHC genes
The term “HLA” was coined by______ because
these were first defined by discovering an antibody
response to circulating WBCs.
JEAN DAUSSET
named according to the product
expressed by the gene locus (capital letter) and the
allele (number)
CAPS - GENE LOCUS
NUMBER- ALLELE
Combination of inherited HLA alleles
HAPLOTYPE
2 KEY FUNCTIONS OF MHC IN ANTIGEN PRESENTATION
- to selectively bind to peptides
- to present peptides on the surface of the host cell to a t cell with a correct t cell receptor
Transplantation Antigens
Serologically Detected Membrane Antigens
Cellular Target Antigens for Cell
Mediated Lympholysis
CLASS 1 - A,B,C,E,F,G,H,X
I -region leukocyte antigen
T and B cell interaction
Immune Response
Mixed Leukocyte Reaction
Tumor Virus Susceptibility
Peptide Transport
Generation of Cytosolic Proteins
Class II - DP DQ DR
DM DN DO
Serum Protein Molecules
Complement Levels, Cytokines and Proteins
Class III - C’
Components,
cytochrome p450, 21
hydroxylases and
TNF
do not respond to host cells in the absence of
foreign peptide
________focus on responding to infected cells but
cannot respond to host cells that are uninfected
t cells
● CD8+ T cell responds to peptide plus self-MHC
CLASS 1
CD4+ T cell responds to peptide plus self-MHC
CLASS 2
The chains that MHC Class I has is _______
also has an independent protein which is the
_________
alpha 1 to 3 chains
beta-2-microglobulin
binding site in class 1
ALPHA 3
coded by chromosome 15
○ just added to the MHC molecule represented
by alpha domains
b2 microglobulin
alpha 1
alpha 2
beta 1
beta 2
CLASS 2 MHC
binding site of class 2
beta 2
Designated as E, F, and G
non classical class 1 mhc antigens
All ________ are not expressed on the cell surfaces
and do not function in antigen recognition but has
other role in immune response
except G
are expressed on fetal trophoblast cells
during the 1st trimester of pregnancy.
G ANTIGENS
It helps ensure tolerance for the fetus by
protecting placental tissue from the action of
NK cells
G ANTIGENS
molecules involved in loading
peptides onto class Il molecules
HLA-DM
controls antigen binding
HLA DO
function remains unknown
HLA DN
ARE NOT ASSOCIATED WITH CELL
MEMBRANE SURFACES
CLASS 3
molecules that bind peptides (8-11 amino
acid long) (Stevens & Miller, 2017) derived from
proteins catabolized in the cytoplasm
CLASS 1
8-11
are transported into the
endoplasmic reticulum where they interact
with newly synthesized MHC Class I
Beta-2-microglobulin chains
PEPTIDES
Smaller peptides are presented by Class
CLASS 1 SMALLER
molecules longer are for Class
CLASS 2 LONGER
In the cytoplasm they meets with the Class I
molecule, they will then be presented in
surface via
exocytosis
Molecules that are found in nearly every nucleated cell
surface
CLASS 1 NUCLEATED
These are molecules that interacts with peptides
(12-17 aa long; Stevens) derived from proteins taken
into cells and catabolized in acid vesicles in APCs.
CLASS 2
12-17
Protein is from the outside (aka exogenous)
CLASS 2 EXOGENOUS
As it enters the APC, it is already in antigen protein form
■ It processes exogenous antigens to the T-helper cells (CD4)
CLASS 2 CD4 TH EXO
endogenous for _____(doon
ginawa sa loob)
● Presents to Tc
CLASS 1 CD8 TC ENDO
Made intracellularly by viruses,
tumors, intracellular pathogens
● They aim to multiply in
the cell
■ Bypass to produce protein inside
class 1
Takes up exogenous antigens
Dendritic cells and macrophages eat it
class 2
Consist of 2 non-covalently bound
polypeptide chains that are encoded by
separate genes in the MHC complex.
major class 2
Are heterodimers because they contain 2 different
chains
major class 2
expressed at the
highest levels; accounts ~ ½ of all class II
MHC molecules on a cell.
HLA -DR
molecules -found in the shortest
HLA DP
- Both are polygenic and are highly
polymorphic in nature - They bind to peptides
- Expressed coordinately and
codominantly
TRUE
can only respond to antigens
when antigens are combined with MC molecules.
T CELLS
Synthesized in the RER
class 1
88-kd membrane-bound molecule in
the ER keeping the a chains partially folded while it is
waiting to bind with the B2-microglobulin.
calnexin
also bind to a chain that is still unpaired with
ß2-microglobulin.
ERp57
Once a chain is bound with ß2-macroglobulin, ______will be released, chaperones
________will join the complex and help
on stabilizing the MHC molecule for peptide binding
calnexin and erp57
calreticulin and tapasin
stabilization until it
reaches the peptides being presented to it
by transporter proteins (TAP)
chaperones
will cut it into smaller pieces/peptides
which will be transported by TAP
proteasomes
transporter proteins of peptide to MHC molecule
TAP
Class II molecules are synthesized in the ER and
associate with the protein:
Ii INVARIANT CHAIN
serves as a chaperone to direct
the aB heterodimer to an endosomal, acidic
protein–processing location
Ii INVARIANT CHAIN
