ADAPTIVE IMMUNO Flashcards
Auto antigen
self antigen
allo antigen
tissue specific antigen (found in one person but not the other)
intracellular pathogens
viruses
exogenous antigens
enter the body and are trapped by APC
Epitope
what the body recognizes
T depedent atnigen
proteins
t independent antigens
poly, lipids, etc..
TCR recognizes
linear protein epitopes
free peptides are
not recognized by TCRs
Immuno dominant epitopes
immune cells present a specific epitope
haptens
small molecules which do not induce immune response alone
-needs to be bound to another molecule or carrier protein
super antigen
- not processed but bind to MHC class w molecules and Vbeta of TCR
- each super antigen activates a distinct set of VB expressing t lymphocytes is expressing
what is an immune complex
Antigen plus antibody
Light chain
kappa or lamda
Papain digestion
releases the 2 sepearate ag binding regions and the Fc region
pepsin digestion
retains single bivalent ag binding capibility and degrades the rest
what is an idotope
the finger like regions that bind to the antigen, also known as the paratope or CDR
Allotype
allelic diferences (subtle differences on the heavy chains)
We all may see an antigen but we respond with different v region deterimants what is this called?
due to idotypic network
IGM
first ab produced, forms a pentamer, (has 10 binding sites)
-Coded by heavy chain mu
IgG
most abunduant one in serum
-ONLY ONE THAT CAN CROSS PLACENTA
ab/ ag binding
due to hydrogen bonds, eletrostatic bonds, wanderwalls, and hydrophoic forces
- each bond is weak but can generate an eletrostaic interaction
- interaction is reversible
Which Ig are predominant for immune responses
-IgG, Iga, Ige
IGA
used for external secretion
IgE
allergy
IGD AND M
found on mature b lymps
Antibody
- 2 heavy chain
- 2 light chain
- chains have a variable region (fAB) AND constant region (fc)
Antibody
- 2 heavy chain
- 2 light chain
- chains have a variable region (fAB) AND constant region (fc)
The strength of the interaction between an univalent ag (epitope) and univalent ab (paratope) is refered to as
affinity
The strength of the interactions ebtween an multivalent ag and a multivalent ab is reffered to as
avididty
if you increase ____ then you increase ____
- valency
- avidity
valency
amount of abs taht are working together
Confimational determant
specific confo has to be made
linear deteminat
must be denatured so the area can bind to it bc if folded its not acceible
noantigenic determinatn
created when you proteolyse somethin
MHC IS ALSO KNOWN AS
HLA
MHC is
polymorphic
MHC are inherited as a
haplotype
Class 1 MHC
- codes for MHC A-G
- EXPRESSED ON all nucleated cells
- presents antigens to CD8+ cytotoxic t cells
- hetrodimer: alpha chain and beta chain (not made from mhc gene)
- alpha 1 and 2 is variable
- it is a membrane bound glycoproein
- has closed ends thus only binds 8-10 peptides
class 1 steps
- virus in cytoplasm, or taken up by pahgosome, or ub protein
- is taken up and then put into proteosome
- makes peptides
- tap takes it in and puts it in the ER and loads it in the receptor
- alpha chain made in ER and beta chain intergraded
- tapasin (cofactor that helps it)
- then that complex is taken to golgi
- and presented
class 2 MHC
composed of a beta chain and alpha chain
- also 4 globular structure
- not covalenly linked
- presents shit to CD4 t lymphocyte (APC cells such as macrophages, dendritic cells, and B lympocytes)
- binds 13-18 polypeptides bc has an open end
CLASS 1 MHC PRESENT WHAT FROM WHERE AND CLASS 2 PRESENT WHAT FROM WHERE
CLASS 1: INTRACEULLAR and SELF
CLASS 2: EXTRA CELLULAR
MHC binding is
-slow: allows peptide to compled with a t cell
antigens entering from the peiohery are filltered by the
lymph and lympoid tissue
antigens in the blood are filtered by the
slpeen
dendritic cells:
macrophages:
b lymphocytes:
present antigen to niave t cells
precent to CD4 effector T cells
present to cd4 T helper cells
Activated DC cells:
loose adhesive markers and upregulate CCR7 (bind to ligand on lympahtic epithelium )
class 2 pathway
- exogenous is taken up and degradaded in endosome
- in the ER MHC is being made and invariant chain is put in to stablize the dimer and block peptides from being put in
- that is fused with with golgi then lysosome
- HLA DM will degrade THE INVARIANT CHAIN AND leave clip
- clip will fall off and then the antigen is then put in and then presented
Cross rpesentation
-dendritic cells can present can pick up host fragments from APC cells and then present them by both MHC 1 and 2
A t helper cell can
release cytokines when activated by a macrpopahge to kill the phaocytosed micobe
or
stimualte b cells when b cells present a MHC with antigen on it to make ab by realsing antibodies
mhc 1 WILL CAUSE WHAT
cause cell to kill it self
Ankylosing spondylitis
inflamation of spine bc individuals are expressing HLA B27
rheumatic fever
patiens who have hla dr 4 allele are more prone to develop a fever
Neuroblastoma
caused by tap
bare lymphocyte syndrome
- tap protein is non functional thus peptides cant enter the ER
- poor responses to viruses
bare class 2
defect in class 2 transactivartor which decreases cd4+
B cell receptor
basically an antibody with an Igb and iga side peice
tcr
has alpha and beta chain
ALSO HAS cd3 and cd3 gamma for singaling
Gene rearragnement events occur in absece of antigen ________.
clonal selection
The production of _____ = production of _____
–production of heavy chain in B cell = prod of beta chain in t cell
-light chain in B cell = alpha chain in T cell
combitorial diversity
-take one of J and then add it to D and then take one of V and add it to DJ
combitoral diveristy occurs by
plandromic sequences called rag 1,2
Junctional diversity
uses TdT to add nucleotides producing variable regions
light chain/ alpha chain only does
VJ
what is the second type of combitoral diveristy
take any heavy chain/ beta that you make and mix it with any light chain/ alpha chain
B cell support
B cells and stem cells interact through VCAM and VLA 4
- releases IL7
- which then releases IL7 CAUSING IT TO MOVE INTO PRO B CELL
Steps to make a mature B cell
in bone marrow:
1) IL7 is released making it into pro b cell
2) rag and tdt expression is increased with then makes the heavy chain and a surrogate light chain (a pre b cell)
3) if the pre bcr works then you inhibit reagarangement of the Ig HEAVY chain locus on the other chromosome
