Activation of Adaptive Immunity Flashcards Preview

HDM Midterm - Brett > Activation of Adaptive Immunity > Flashcards

Flashcards in Activation of Adaptive Immunity Deck (29)
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1
Q

What are the two ways an APC (macrophage or dendritic cell) can activate a T cell?

A
  1. TLR binds a PAMP then produces cytokines (IL12, 6, TNF alpha)
  2. takes in pathogen/Ag, chews it up, throws it out on an MHC for TCR to see
2
Q

Where are type 2 HLA found?

A

APCs: Dendritic cells, macrophages, b cells and T helper

3
Q

Where is HLA controlled from?

A

Chromosome 6

4
Q

How many haplotypes does a human have for HLA?

A

2, one from mom, one from dad

5
Q

What are the class 1 HLA genes?

A

HLA-A, HLA-B, HLA-C

6
Q

Where are class 1 expressed? What do they do?

A

All nucleated cells, present antigen to CTL and inhibit NK cells

7
Q

What are the parts of HLA 1?

A

Three alpha units and 1 beta unit

8
Q

What regions of HLA 1 are encoded by HLA?

A

a1, a2, a3

9
Q

What limits the size of HLA1 peptides?

A

Closed ends on the protein, limits to 8-10 AA

10
Q

Where is HLA 1 made?

A

In the ER as a glycoprotein, in the ER the beta subunit associates, then in the ER the peptide binds to the receptor and moves to the cell surface

11
Q

What are the HLA 2 subtypes?

A

HLA-DP, HLA-DQ, HLA-DR

12
Q

What is the structure of HLA2?

A

It is made of an alpha and beta unit which are roughly mirrors of each other

13
Q

How many peptides does HLA2 bind?

A

Between 13-18 because the ends are open

14
Q

What domains of HLA2 have the greatest polymorphism? Where are they from?

A

a1, b1, they come from DQ

15
Q

What binds to HLA2 in the ER? What does it do?

A

Invariant chain, it directs the protein to an endosome where the invariant protein is removed and the peptide is allowed to bind

16
Q

How many alpha and beta chains do we have for HLA2?

A

6a and 6b; you get 3 from each parent and they can combine in any combination of a and b

17
Q

What are the features of peptide binding to HLA

A

They are slow to bind and even slower to come off because you want T and B cells to be able to recognize the protein as problematic before it is removed

18
Q

What are our antigen presenting cells?

A

B cells, macrophages, dendritic cells

19
Q

What is the HLA2 pathway for antigen processing?

A

The protein is taken into the cell-> endosome and lysosome bind and degrade the protein -> HLA2 is made in ER and invariant chain is attached -> endosome carrying degraded protein and HLA2 are fused -> CLIP removes portion of invariant chain -> HLA-DM removes CLIP from HLA2 -> protein binds to HLA2 -> whole complex is transported to cell surface

20
Q

What is the pathway for HLA1 antigen processing?

A

Protein inside cells is degraded by proteasome -> degraded pieces are taken up by TAP which moves it into the ER lumen -> TAP is connected to HLA1 by tapasin on the lumen -> the complex forms -> moves to golgi -> vesicles dumps complex in cell surface

21
Q

What is cross presentation?

A

When one thing is recognized by both CD8+ and CD4+ t cells

22
Q

What is Ankylosing spondylitis associated with?

A

Inflammation of the spine based on overexpression of HLA-B27

23
Q

What is rheumatic fever?

A

After effect of S. Pyogenes infection; Ab created cross react with the heart

patients with HLA-DR4 allele are more likely to get it

24
Q

What is sjogren’s syndrome?

A

Associated with HLA-DR3

Defect in salivation and lacrimation

25
Q

What HLA is Type 1 DM associated with?

A

HLA-DQw8

26
Q

What HLA is psoriasis associated with?

A

HLA-B3

27
Q

What cancer has an antigen processing defect?

A

Renal cell carcinoma

Down regulated TAP protein (transports peptides into ER lumen)

28
Q

What is bare lymphocyte syndrome?i

A

Defect in TAP protein that doesn’t transport peptides in so there are no peptides expressed on the cell surface (no HLA1 on cell surface)

29
Q

What are the symptoms of bare lymphocyte syndrome?

A

Chronic respiratory infection and poor response to viruses