Immunology Chapter 5

Define polymorphism

The large variance in genes in the human population

What type of antigen can bind to T cells (α & β)?

Protein

Ag-presenting glycoproteins are also referred to as ______

MHC molecules

A TCR receptor is composed of a ___ and ___ chain

α and β

TCRs have different effector functions (T/F)

False

What are the adaptive T cells?

α & β

What are the innate T cells?

γ & δ

Which of the following chromosomes in the TCR α chain locus found on?
A) Chromosome 11
B) Chromosome 7
C) Chromosome 14
D) Chromosome 22

C

The TCR β chain locus is located on chromosome ___

7

The β chain contains _____ segments

V, D, and J

The α chain contains V & J segments (T/F)

True

Where does T cell development take place?

Thymus

What is the CD3 complex composed of? And how many of each protein?

CD3γ x1, CD3δ x1, CD3ε x2

What are the components of an α:β heterodimer?

CD3 complex, ζ chain

What chromosome is the CD3 complex found on?

Chromosome 11

The ζ chain is found on chromosome 7 (T/F)

False; found on chromosome 1

Lack of functional CD3δ & CD3ε can lead to what?

Immunodeficiency

Can a cell express both γ:δ TCR and a α:β TCR at the same time?

No

What is the dominant T cell population in epithelial tissue? γ:δ T cell or α:β T cell

γ:δ T cell

Do γ:δ T cells use co-receptors?

No

What kind of cell would a γ:δ T cell act most like?
A) Macrophage
B) NK cell
C) Dendritic cell
D) α:β T cell

B

What is the main type of T cell found in your body right now?

α:β T cell

The γ chain locus is on chromosome ___ and the δ chain locus is on chromosome ___

7; 14

Where are the δ gene segments found?

Between the Vα and Jα segments on chromosome 14

What is deleted/inactivated when the α-gene is rearranged?

δ chain

How does the δ chain increase junctional diversity?

Adding more than one D segment

Which contains more variability, the δ chain or the γ chain?

δ chain

Which of these additional proteins do B cells require to recognize an antigen?
A) MHC Class II
B) CD3 complex
C) LPS
D) None of the above

D

What is required to happen before a peptide is presented by an MHC molecule?

Protein must be broken down

What is the heavy/α chain of MHC class I composed of?

α1-3 domains, β2 micro-globulin

MHC class I molecule's light chain is composed of the following:
A) α1 and α2
B) MHC class I does not contain a light chain
C) β2
D) A&C

B

Name the components of MHC class II

α1&2, β1&2

____ makes up the binding group for MHC class I, while ____ makes up the binding group for MHC class II

α1 & α2, α1 & β1

We get diversity in MHC from ______

Polymorphism

Which of the following would be an example of an extracellular pathogen?
A) Bacteria
B) Parasites
C) Viruses
D) A&B
E) None of the above

A

A virus would be considered what type of pathogen?

Intracellular

MHC class I presents the antigens of ______ pathogens, and MHC class II presents the antigens of
_______ pathogens

Intracellular; extracellular

Which of the following would MHC class I recognize?
A) Staphylococcus aureus
B) HIV
C) E. Coli
D) A & B
E) A & B & C

B

CD4 and CD8 can be described as T cell co-receptors. (T/F)

True

CD8 binds to MHC class __ (I or II)

I

CD4 binds to MHC class __ (I or II)

II

What is the function of CD4 T cells?

Help other immune cells respond to extracellular sources of infection

What is the function of CD8 T cells?

Cytotoxic, tell infected cells to die by apoptosis

Can both CD8 and CD4 differentiate into differentiation patterns? If not, then which one can?

No, only CD4

CD_ T cells respond to extracellular pathogens, and CD_ T cells respond to intracellular pathogens

4; 8

What is the function of TH1 cells?

Activates macrophages by producing IFN-γ

What do TH2 cells do?

Stimulates B cells to make antibodies

Could a CD8 T cell recognizing MHC class I be considered naïve?

No

What is a dendritic cell?

An antigen-presenting cell present in tissues

Does IL-4 or IL-5 stimulate B cells?

IL-4

Which of the following CDRs would most likely contain the most diversity?
A) CDR1
B) CDR2
C) CDR3
D) A & B

C

How many binding sites does a TCR have for an antigen?

1

A TCR has __ chains, __ CDRs, and __ binding sites

2; 6; 1

What is multipoint attachment?

Multiple peptides of the same amino acid sequence that are loaded on the MHC

Which of the following occurs prior to Ag stimulation for both B and T cells?
A) RNA splicing
B) Somatic hypermutation
C) Gene arrangement
D) All of the above
E) None of the above

C

Which of the following is NOT similar between both T cell and B cell gene rearrangement?
A) TdT adding N-nucleotides
B) Gene segments flanked by RSS
C) RAG complex creating DNA hairpin
D) Use of AID

D

MHC Class I has __ α chains, while MHC Class II has __

3; 2

MHC Class I loads ____ amino acids in length, while MHC Class II loads ____ amino acids in length.
A) 3-6; 6-12
B) 8-10; 10-25
C) 10-25; 8-10
D) None of the above

B

What is meant by promiscuous/degenerate binding specificity?

Each MHC molecule has the ability to bind to thousands of different peptides with different amino acid sequences

In which class of MHC is the peptide pinned into the end pockets ?

Class I

What kinds of cells can use MHC Class I?

All nucleated cells

All of the following can express MHC Class II EXCEPT:
A) Macrophages
B) Dendritic cells
C) T-Cells
D) B-Cells
E) All of the above can use MHC Class II

C

Would we expect CD8 and CD4 to bind to the TOP of the MHC?

No

Where on their corresponding MHC molecules do CD8 and CD4 bind, respectively?

α3 domain; β2 domain

Would we expect to find a peptide 13 amino acids in length on a MHC Class I molecule?

No

A peptide found on MHC Class I may have hydrophobic or basic residue at its ____ terminus

Carboxyl

Would a constitutive proteasome or an immunoproteasome be used more frequently in an infected cell?

Immunoproteasome

β1i codes for ___, and β5i codes for ___

LMP2; LMP7

Immunoproteasome subunits are more likely to cut after hydrophobic residues. (T/F)

True

Expression of immunoproteasome subunits is induced by which of the following?
A) IL-1
B) IFN-β
C) IRF7
D) IFN-γ

D

What is the function of TAP?

Transports peptides from the cytosol to the lumen of the E.R.

Where is TAP located?

E.R. membrane

TAP is a (hetero or homo) dimer composed of TAP-1 and TAP-2.

Hetero

What do chaperones do?

Assist in correct folding and assembly of proteins

Suppose we find an elongated polypeptide. On what terminus would we find the excess residue?

N terminus

What is the function of calnexin? What causes it to release?

Retains partly folded α chain on MHC Class I in the E.R.; released when β2-microglobulin binds

To form a peptide loading complex, tapasin and calreticulin bind to ___

TAP

Where does MHC Class I processing take place?

E.R.

What is left behind when the invariant chain is broken down?

CLIP

HLA-DM is a MHC Class II molecule and doesn't present peptides to T cells. (T/F)

True

A patient has less than 1% of normal MHC Class I levels and has non-functional TAP. What would be their diagnosis?

Bare lymphocyte syndrome

Where in the cell would we expect to find MHC Class II molecules being loaded with polypeptide?
A) Cytosol
B) E.R.
C) Golgi Apparatus
D) Endosome
E) None of the above

D

Which of the following is FALSE regarding the function of the invariant chain?
A) Blocks binding groove on MHC Class II
B) Sends MHC Class II to MIIC
C) Allows for peptides in cytosol to enter the E.R.
D) A & B

C

What is the other way the invariant chain is denoted?

li

After HLA-DM facilitates the release of ____, MHC Class __ is ready to present to CD_

CLIP; II, 4

Would we expect to find an MHC Class I outside of the E.R. without a peptide bound?

No

What kind of cell can activate naïve T cells?

Dendritic cells

P-APC stands for ______ and is used to describe what type of cells?

Professional Antigen Presenting Cell; dendritic, macrophage, and B cells

In a population, what is the most polymorphic set of genes?

MHC genes

The encoded proteins of an allele is called a(n)
A) Allotype
B) Haplotype
C) Isoform

A

Define haplotype

Cluster of polymorphic genes

An individual inherited the same form of the HLA-E from both parents. Are they heterozygous or homozygous for the HLA-E gene?

Homozygous

Alleles cannot be co-dominantly expressed. (T/F)

False

If someone is heterozygous at each loci for MHC Class I & II genes, how many presenting molecules do they have?

12

Name the 3 MHC Class I isotypes

HLA-A, HLA-B, HLA-C

Which of the following are NOT MHC Class II isotypes?
A) HLA-DR
B) HLA-F
C) HLA-DP
D) HLA-DQ
E) A & C

B

Could HLA-DP present peptides to CD8 T cells?

No

Which MHC Class I isotype can act as an inhibitory ligand for NK cells?

HLA-E

Where would we expect to find allotype variability in HLA Class I molecules?

α1 & α2 domains

It would be normal to find variable region domains in MHC molecules. (T/F)

False