L6-Exam 2

Question 1

The typical virus replication cycle has both ___ and ___ phase

Answer 1

extracellular and intracellular phase

Question 2

Can antibodies gain access to the intracellular environment?

Answer 2

No - it is the job of the T-Lymphocyte system to recognize intracellular antigens

Question 3

In order for T cells to recognize antigens derived from within a host cell, what must happen to the antigen first?

Answer 3

Antigen must be processed

Question 4

The exogenous antigen processing pathway involves ____ molecules and activation of ___ cells

Answer 4

-HLA Class II molecules
-CD4+ T Helper cells

Question 5

The endogenous antigen process pathway involves ___ molecules and activation of ___ cells

Answer 5

-HLA Class I molecules
-CD8+ cytotoxic T cells

Question 6

Nearly every vertebrates has an MHC that encodes genes responsible for determination of ___

Answer 6

self and non-self

Question 7

MHC Class I and II genes encode ____ class I and II

Answer 7

HLA Class I and II

Question 8

Genes for MHC are closely linked on chromosome __

Answer 8

Chromosome 6 (there are 6 main loci)

Question 9

What are the three loci that make up HLA Class I? Class II?

Answer 9

HLA Class I: HLA-A, B, and C
HLA Class II: HLA-DP, DQ, and DR

Question 10

True or False: Genetic polymorphisms exist in the MHC complex genes

Answer 10

True - each gene has multiple alleles

Question 11

How many sets of MHC genes does each person have? How are they inhertited?

Answer 11

two sets of MHC
inherited en bloc

Question 12

What family does the MHC complex belong to?

Answer 12

IgG Superfamily Gene

Question 13

Based on the structure, label these as either HLA Class I or HLA Class II:

Answer 13

HLA Class I (left) and HLA Class II (right)

Question 14

What are three features shared by HLA Class I and HLA Class II molecules?

Answer 14

1) Peptide binding groove
2) Binding site for co-receptor on T cell
3) Transmembrane glycoproteins (activates signaling molecules)

Question 15

What are three features not shared by HLA Class I and HLA Class II molecules?

Answer 15

1) Structure
- HLA Class I is a monomer
- HLA Class II is a dimer

2) T Cell Interaction
- HLA Class I has a CD8 binding site
- HLA Class II has a CD4 binding site

3) Expression
- MHC I is expressed on all nucleated cells
- MHC II expressed on APC (dendritic cells)

Question 16

Which of the following associations are correct:
A. MHC I - endogenous
B. MHC II - endogenous
C. MHC I - exogenous
D. MHC II - exogenous

Answer 16

A and D

Question 17

Which of the following associations are correct?
A. HLA-A - exogenous
B. HLA-DQ - exogenous
C. HLA-DP - endogenous
D. HLA-C - exogenous

Answer 17

B. HLA-DQ - exogenous

Question 18

Which side is peroxidase independent vs. peroxidase dependent?

Answer 18

Left side (peroxidase independent) while right side (peroxidase dependent)

Question 19

In processing of an exogenous antigen, HLA class II molecules are made in the ___

Answer 19

ER

Question 20

What are the two roles of the invariant chain in processing of exogenous antigen?

Answer 20

1) Blocks peptide binding groove
2) Ensures alpha and beta stay in right configuration

Question 21

Once a microbe gets phagocytose in exogenous antigen processing, a ___ fuses with the phagocytic vesicle and the proteins are broken down

Answer 21

granule

Question 22

Once HLA Class II molecules are formed and have invariant chain added (in exogenous antigen processing) - they move to the ___ for further processing

Answer 22

Golgi

Question 23

The endosome fuses with what was phagocytosed to create the ___ endosome. In this endosome, ____ cleaves the invariant chain, leaving a ___

Answer 23

late; proteolytic activity; clip

Question 24

____ is the site of diversity in processing of exogenous antigens, as it is where peptides with the most affinity for the peptide binding groove site bind

Answer 24

Late endosome

Question 25

Once processing of exogenous antigens has occurred, HLA molecule fuses with the lipid bilayer and presents to ___

Answer 25

CD4

Question 26

If the cell can express HLA Class II, it can process and present intracellular __ to _____

Answer 26

Ag to CD4+ T Helper Cells

Question 27

HLA Class II cells are constitutively expressed on what three cell types?

Answer 27

1) Dendritic cells (spleen/lymph nodes)
2) Thymic epithelial cells
3) B cells

Question 28

Expression of HLA Class II can be induced on what three cell types?

Answer 28

1) Macrophages
2) Fibroblasts
3) Endothelial cells

Question 29

If CLIP bound to MHC II irreversibly, what would happen?
A. Self peptides would be presented
B. Exogenous peptides would be presented
C. No peptides would be presented

Answer 29

C. No peptides would be presented

Question 30

When an endogenous antigen, such as a virus, enters a cell, viral nucleic acid is made in the nucleus then made into a protein, which is ____

Answer 30

ubiquinated (targets protein for recycling)

Question 31

During endogenous antigen processing, then antigen is broken down into peptides via the ______. Once made, peptides enter the ER via ___

Answer 31

proteosome; TAP1 and TAP2

Question 32

During endogenous antigen processing, MHC Class I chains and B2m are made in the ___ and assembled with ____

Answer 32

ER; caparones

Question 33

What type of cells can process endogenous Ag?

Answer 33

All nucelated cells (exception: neutrophils)

Question 34

Peptides generated within the cytosol of a host cell are likely to become associated with which of the following MHC-encoded molecules?
A. HLA Class I
B. HLA Class II
C. Both HLA Class I and HLA Class II
D. Neither HLA Class I or HLA Class II

Answer 34

A. HLA Class I

Question 35

Which of the following MHC-encoded molecules are responsible for presenting antigenic peptides that are derived from phagocytosis or endocytosis?
A. HLA Class I
B. HLA Class II
C. Both HLA Class I and HLA Class II
D. Neither HLA Class I or HLA Class II

Answer 35

B. HLA Class II

Question 36

Influenza vaccine contains dead virus particles. Antigens in this vaccine will most likely activate?
A. CD3+/CD8+ Cytotoxic T Lymphocytes
B. CD16 / CD56 NK cells
C. CD3+ and CD4+ Helper T Cells

Answer 36

C. CD3+ and CD4+ Helper T Cells