Lecture 21: Antigen Capture and Presentation Flashcards

1
Q

Class I MHC genes

A
  • encoded by 3 different regions in locus
    • HLA-A/B/C
  • on all NUCLEATED CELLS
  • present to Cytotoxic T-Lymphocytes
  • inhibitory receptor for NK cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Class I MHC structure

A
  • heterodimer of two proteins
  1. alpha chain (MHC encoded)
    • membrane bound glycoprotein
  2. beta2 microglobulin (non MHC encoded)
    • associates non-covalently with alpha3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Class II MHC genes

A
  • encoded by HLA-D region
    • membrane bound glycoproteins
  • on antigen-presenting cells
  • presents to CD4+ T cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

HLA peptide binding

A
  • low affinity interaction (slow on rate, very slow off rate)
  • allows complex time to interact with T-lymphocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

H-Y (minor MHC/HLA)

A
  • coded on Y chromosome

- associated w/acute rejection of male grafts in female recipients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What domains on the MHCI/II complexes do CD8 and CD4 recognize?

A

CD8 –> binds to alpha3 domain on MHCI

CD4 –> binds to beta2 domain on MHCII

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What T cells do dendritic cells, macrophages, and B lymphocytes present to?

A

DC –> naive T cells (initiation of T cell responses to protein antigens)

Macrophages –> CD4+ effector T cells (effector phase of cell-mediated immune response)

B lymphocytes –> CD4+ T helper cells (humoral immun response)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Plasmacytoid Dendritic Cells

A
  • found in blood/tissue
  • promote innate anti-viral state (produce Type 1 interferons)
  • expresses TLR 7 and 9
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Dendritic Cell Activation

A
  • lose adhesion markers and upregulate CCR7
  • inc. MHC and CD80 expression
  • travels to 2nd lymphoid tissue
  • mature as migrate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Ankylosing Spondylitis

A
  • spine inflammation
  • 88% express HLA-B27 allele
    • cannot bind critical antigenic peptide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Rheumatic Fever

A
  • Abs for streptococci cross react with cardiac tissue

- patients w/HLA-DR4 more likely to develop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Bare Lymphocyte Syndrome

A
  • TAP protein nonfunctional, peptides can’t enter ER
  • cells cannot present antigens
    symptoms: chronic respiratory infections, poor responses to viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Bare Lymphocyte Syndrome Class II

A
  • inherited defect in CIITA (deficiency in HLA Class II expression, non-functioning T lymphocytes)
  • HLA II genes turned on by CIITA, RFX5, RFXAP, RFXANK
  • mutations in these Transcription Factors lead to dec. expression of Class II gene products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly