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53 Cards in this Set

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What are the major players in adaptive immunity?
T and B cells
Which cells can eliminate the source of virus during an infection?
Only T cells
What is the half life of an immunoglobulin?
30 days
If you infect a mouse with a virus, wait ~7 days, and transfer the Ab produced to another noninfect mouse, will they be protected vs the virus?
Yes - this is passive immunization
What about if you transfered the T cells from the infected mouse, will the noninfected mouse be protected from viral infection?
yes - but only if the mouse is genetically identical!
What is the term for genetic identity?
Syngeneic
What is allogeneic?
Genetically different - a different strain.
Why do Tcells transferred to an allogeneic mouse not confer protection against viral infection?
Because Tcells always recognize foreign antigen in the context of self.
What is MHC restriction?
The requirement Tcells have for Antigen presentation - even if they are specific for that antigen, it must be on top of self MHC.
So when is Tcell transplant useful?
Only when the recipient is genetically identical
If you transplant a tumor from one mouse into a genetically identical mouse (syngeneic) will it be rejected?
No
If you transplant the same tumor into an allogeneic mouse will it be rejected?
Yes.
If you make baby mice from allogeneic mice and transplant a tumor from either parent into the baby mice, will it be rejected? Why?
No - because the genetic locus responsible for tissue rejection is CODOMINANT - surface markers from both mom and dad expressed.
What is the genetic locus responsible for issue rejection?
Major Histocompatibility Complex (MHC)
On what chromosome is MHC?
Ch' 6
How many genes are encoded within MHC?
>200
What are the genes for MHC class I?
HLA-A
HLA-B
HLA-C
What are the genes for MHCII?
HLA-DR
HLA-DQ
HLA-DP
How many genes make up each component of MHC II?
2 - each has an alpha and a beta
How many base pairs does MHC span?
~7 million
Why are MHC class I and II genes so special?
They are the most polymorphic genes in the genome!
3 terms that we use to describe the MHC locus:
-Polymorphic
-Polygenic
-Codominant
What does polygenic mean?
There are different genes that encode MHC I and II within one person - HLA-A, B, or C for example.
What does Polymorphic mean?
The likelihood of two people having the same HLA-A or HLA-B or HLA-C is very unlikely, because many different alleles for these genes have been identified within the population.
What does codominant mean?
That we express the HLA genes from both mom and dad equally, so each person really has 6 different types of MHC I on their cells.
What are the chances that 2 siblings have identical MHC genes?
1/4
What cells express Class I MHC?
All nucleated cells
What do Class I MHC molecules play a major role in?
Allograft rejection
What cells do MHC I molecules present antigen to?
CD8 pos Tc cells
What makes up the structure of MHC class I?
A heterodimer composed of
-class I heavy chain
-B2microglobulin light chain
What is another name for the big heavy chain of MHC I?
Alpha chain
What does the alpha chain consist of?
3 alpha subunits
Which part of MHC I is encoded in MHC?
only the alpha chain
Which part of MHC class I spans the membrane?
The c-terminal end of the alpha chain
Where are the polymorphic residues of MHC Class I?
In a1 and a2 domains which make up the peptide binding cleft.
What is essential for Class I MHC structural stability?
Binding of peptide within the cleft
What cells express Class II MHC?
Specialized APCs
-B cells
-Macrophages
-Dendritic cells
What do Class II MHC molecules play a major role in?
Allograft rejection (along with MHC I)
To what cells do Class II MHC molecules present antigen?
CD4pos Thelper cells
What makes up the structure of MHC class II?
A heterodimer composed of:
-alpha chain
-beta chain
Which components of MHC II are encoded in MHC?
Both! A and B
Which component of MHC class II is more polymorphic?
Beta chain
Which chains of MHC II are tissue typed for tissue transplant?
Only the beta chains
What must be present in order for a tcell receptor to recognize antigen on an APC?
A COMBINATION OF BOTH
-peptide antigen
-MHC molecule
What is the importance of the many polymorphisms of the Class I MHC heavy chain and Beta chain of Class II MHC?
They have a direct effect on which antigens can bind to the MHC molecules.
Which MHC class II gene product is the most polymorphic?
The beta chain of DR
Which MHC Class I gene product is most polymorphic?
HLA-B
What is the size limit for peptides binding Class I MHC?
8-10 AA's long
What is the size limit for peptides binding Class II MHC?
12-16 AA's long
How can MHC molecules bind to a wide variety of peptides?
They recognize a few "anchor" residues, but the rest can vary
What makes HLA-A B or C different?
Each binds a distinct set of peptides
What is ankylosing spondylitis?
An inflammatory disease of vertebral joints
What predisposes individuals to AS?
Possessing HLA-B27