Lecture 5 - Antigen Presentation and the MHC

Question 1

After an antigen enters the body, what immune cells will it stick to? Specifically, what will it stick to on the cell?

Answer 1

They stick to TLRs on antigen presenting cells.

Question 2

What are the three important antigen presenting cells?

Answer 2

1. Dendritic cells
2. Macrophages/monocytes
3. B-lymphocytes

Question 3

Do APCs release cytokines after they bind an antigen on their TLRs?

Answer 3

Yes!

Question 4

Which cytokines make endothelial cells sticky?!? How?

Answer 4

IL-1 and TNF. They activate the endothelial cells to make adhesion molecules (like selectins).

Question 5

After endothelial cells are made sticky, what happens?

Answer 5

Polymorphonuclear leukocytes will slow down and roll along the endothelial cells until they infiltrate between the cells to get to the antigen site.

Question 6

What do IL-1 and TNF do to the liver?

Answer 6

They activate it to release acute phase proteins such as C-reactive protein (CRP)

Question 7

What does CRP indicate to a clinician?

Answer 7

The activity of a disease.

Question 8

Which cytokines affect the hypothalamus to produce fever, depression (sickness cytokines)?

Answer 8

IL-1 and TNF

Question 9

Name five chemokines that APCs make.

Answer 9

1. IFN alpha
2. IFN beta
3. IL-6
4. IL-12
5. IL-10

Question 10

What do IFN alpha and beta do?

Answer 10

Kill viruses (antiviral proteins)

Question 11

What does IL-6 do?

Answer 11

Activates bone marrow to increase WBC count

Question 12

What does IL-12 do?

Answer 12

Activates T cells and NK cells

Question 13

What does IL-10 do?

Answer 13

It is the inhibitory cytokine

Question 14

Where do APCs go once they bind an antigen?

Answer 14

To the lymph nodes to interact with T cells.

Question 15

Where are the MHC genes located in the human genome?

Answer 15

Short arm of chromosome 6

Question 16

What class are the B, C, and A MHCs part of?

Answer 16

Class I

Question 17

What class are the DP, DQ, and DR MHCs part of?

Answer 17

Class II

Question 18

What is the most polymorphic system in biology?

Answer 18

The MHCs (aka HLAs - human leukocyte antigens)

Question 19

Which HLA molecules are found on the surface of APCs?

Answer 19

All of them!

Question 20

On which cells are MHC class I molecules found?

Answer 20

All nucleated cells (everything except RBCs)

Question 21

On which cells are MHC class II molecules found?

Answer 21

APCs only!

Question 22

What additional protein is part of the MHC class I molecule on the cell surface?

Answer 22

Beta-2 microglobulin

Question 23

Are beta-2 microglobulin genes polymorphic?

Answer 23

Nope - they are located on a different chromosome than the MHC molecules

Question 24

Which disease is HLA B27 often associated with?

Answer 24

Ankylosing spondylitis aka bamboo spine

Question 25

Which MHCs are narcolepsy associated with?

Answer 25

DR2 and DQ1

Question 26

Which disease is associated with DR3 and DR4?

Answer 26

Type I diabetes mellitus (IDDM)

Question 27

Which disease is associated with HLA DR4?

Answer 27

Rheumatoid arthritis.

Question 28

Which molecules are the targers of organ transplant rejection?

Answer 28

The MHC molecules.

Question 29

Which subunits make up a MHC class II molecule?

Answer 29

Two alpha and two beta subunits.

Question 30

Which subunits make up a MHC class I molecule?

Answer 30

Three alpha subunits and a beta-2 microglobulin.

Question 31

Which cells produce interferon gamma and what does it do?

Answer 31

NK cells primarily produce it. It activates macrophages to express increased DR molecules. This was not covered in class but is in the practice quiz.