Antigen presentation and the MHC Flashcards Preview

HD exam one > Antigen presentation and the MHC > Flashcards

Flashcards in Antigen presentation and the MHC Deck (35):
1

Location of macrophages

Blood, liver, spleen

2

location of dendritic cell

Skin, lymphoid tissues

3

Location of B cells

Lymphoid tissues, infection sites

4

Macrophages in the different parts of the body

Microglia in the brain, Kupffer cells in the liver

5

Skin APCs

Langerhans cells, which line the junction of the dermis and epidermis

6

How do skin APCs help the immune response?

They travel to the paracortex and present to the T cells there

7

Plasmacytoid dendritic cells

Produce large quantities of interferon in response to viral infections

8

Conventional dendritic cells

Undergo a maturation process

9

From what are antigenic peptides usually derived on an MHC I molecule?

Viruses that have taken over the cell

10

How are invaded viruses made into antigens?

Proteosomes in the cell degrade them and put them on the MHC (subunits LMP2 and LMP7)

11

Transport of peptides to the MHC

Transported by TAP-1 and -2

12

ER antigen chaperones

Erp57, calnexin, calreticulin

13

What is the purpose of ER chaperone proteins?

Blocks the MHC from being bound by anything other than its antigen

14

ERAAP

Removes the chaperone proteins and allows the binding of the antigen to MHC in the endoplasmic reticulum

15

After the antigen is attached in the ER, what happens?

The antigen complex moves through the golgi body, is put into a vesicle, and transported to the cell surface

16

From what are MHC class II antigens derived?

The products of degradation from phagocytosed substances

17

What is the associated protein with MHCII?

Ii

18

How is Ii removed from the complex?

Acidification

19

What is left in Ii's spot after acidification?

CLIP

20

What loads/unloads CLIP from the complex?

DM

21

What is displayed in the MHC complexes when there is no foreign antigen?

Class I: self antigen
Class II: CLIP

22

Th1 cells

Activate macrophages

23

Th2 cells

Induce antibody synthesis

24

B7

Also known as CD80 or CD86; co-stimulatory molecule on APCs

25

What are the two signals necessary for activation of T cells?

Binding to the MHC and also the interaction of B7 with CD28

26

Why would an APC not express B7?

When they take up antigens that are not microbial, they don't always express B7

27

What happens when B7 is not expressed?

When T cells recognize the MHC on an APC, they stimulate the APC to express CD40, which binds to the CD40L on the T cell and takes the place of the B7/CD28 interaction

28

What is the interaction between B7 and CD28?

CD28 cleaves B7 and then induces T cell proliferation and differentiation

29

What stimulates the B cell to make B7?

Presence of the antigen on the MHC

30

What happens after MHC-peptide engagement?

TCR initiates a phosphorylation cascade that triggers a lot of branching pathways

31

Time course of MHC-peptide engagement

If bound for a short period of time, killer T execution will be activated; however, complex functions like T cell proliferation take a connection that lasts minutes-hours

32

Mature immunological synapse

Specific pattern of receptor recognition with a central cluster of TCRs surrounded by a ring of adhesion molecules

33

Intermediate ring

Enriched with adhesion molecules like LFA-1 and ICAM-1 that promote efficient TCR-MCH-peptide interaction and lead to a biological response

34

Location of ICAM-1 and LFA-1

LFA-1: T cell surface
ICAM-1: APC surface

35

Inner circle

TCR, CD4, and co-stimulatories