10. Immunology Revision Lecture - Ian Todd Flashcards Preview

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1
Q
  1. Explain the main things involved in innate immunity
  2. Explain the main things involved in adaptive immunity
  3. What kind of cell is usually an APC?
A
  1. PAMPs / PRRs
  2. Tc / Bc / antigen / APC / Ig
  3. Dendritic cell
2
Q

What is complement and what does it do?

A

Complements are proteins and they complement the effect of antibodies

3
Q

Describe how to get to C3 convertase via the 3 complement pathways

A

MBL pathway
MBL (mannon binding lectin) + microbial mannose
Activates serine proteases MASP-1 and MASP-2
Breaks down C4 and C2
C4b2a = C3 convertase

Classical pathway
Antigen bound to antibody (IgG or IgM) bound to C1q
Activates C1r and C1s
Breaks down C4 and C2
C4b2a = C3 convertase

Alternative pathway
C3b + covalently bound to microbial surface + Factor B fragment b + properdin
C3bBbP = C3 convertase

4
Q
  1. C3b is constantly being made in the body but is rapidly degraded. What is this called?
  2. What can be done to stop the degradation?
A
  1. Tick over pathway

2. Stabilise by binding

5
Q
  1. Role of C3a?

2. Main role of C3b?

A
  1. Mast cell activation and neutrophil recruitment

2. Opsonisation

6
Q
  1. What 2 things split up C5?
  2. What is the role of C5a?
  3. What is the role of C5b?
A
  1. Mast cell activation and neutrophil recruitment
  2. Membrane attack pathway leading to membrane lysis
    Membrane attack complex makes a hole in microbial membrane
    Poly form of C9 + C6 / C7 / C8
7
Q
  1. What do T cells originate from?
  2. Th cells: express? Peptide on APC? Type of protein?
  3. Tc cells: express? Peptide on APC? Type of protein?
  4. How do you activate a T cell?
  5. What is the main APC for naive T cells?
A
  1. Lymphoid stem cells
  2. CD4+ / HLA class 2 / exogenous proteins
  3. CD8+ / HLA class 1 / endogenous proteins
  4. Activate signalling pathways in the T cell
  5. Myeloid dendritic cell
8
Q
  1. Activated Th1 cell: identify microbial peptide on what? Secrete what? Give an example.
  2. Activated Th1 and Th2 cells: drive which 2 things? What does it do to B cell + Ag + Ig?
  3. What is the majority of the cytokines that Th1 releases? What does it encourage the class switching to?
  4. What are the majority of cytokines that Th2 releases? What does it encourage the antibody production of?
A
  1. APC / cytokines / IFN gamma
  2. B cell activation and Ab production / internalises the complex into the cytoplasm
  3. IFNgamma
    IgG (1-3)
  4. IL4 / IL5 / TGFbeta
    IgG(1-4) / IgE / IgA
9
Q

What are the two ways that a Tc cell can trigger cell death? What is the final outcome of these 2 methods?

A

Secreting perforins and granzymes
Expressing the Fas ligand
Apoptosis

10
Q
  1. T cell antigen receptor: polypeptide chains? Domains? Combining site? Function?
  2. What do Th cells do? What does this result in?
  3. What do Tc cells do?
  4. T cell recognition: what must the antigen be? Binding?
  5. How do Th0 cells polarise into Th1 and Th2 cells?
A
  1. 2 = Alpha and beta
    Variable and constant
    V-alpha and v-beta = antigen specificity
  2. Help activate other cells of the immune system mainly B cells and macrophages leading to antibodies and phagocytosis
  3. Kill infected cells
  4. Protein
    T cell can’t bind directly so the antigen has to go inside an APC, undergo antigen processing, and then be presented as a peptide on the surface of a cell
  5. Th0 cells exposed to IL-12 polarise into Th1
    Th0 cells exposed to IL-4 polarise into Th2
11
Q

What activates the APC?

What kills the APC?

A

Th cell + antigen activates APC

Tc cell + antigen kills APC

12
Q

HLA class 1

  1. Binds to which T cell?
  2. How many polypeptide chains and what are the called?
  3. Which chain is in the membrane of the APC?
  4. Which domains make up the peptide binding cleft?
A
  1. Tc cell
  2. 2 chains = alpha and beta
  3. Alpha chain
  4. alpha 1 and alpha 2 = peptide binding cleft
13
Q

HLA class 2

  1. Binds to which T cell?
  2. How many polypeptide chains and what are the called?
  3. Which chain is in the membrane of the APC?
  4. Which domains make up the peptide binding cleft?
A
  1. Th cell
  2. 2 = alpha and beta
  3. Both chains in membrane of APC
  4. Alpha 1 and beta 1 = peptide binding cleft
14
Q

Explain antigen processing with HLA class 2 and Th cells

A
Exogenous antigen
Endocytosis (in a vesicle = endosome)
Proteolytic enzymes pumped in
Antigen broken into peptides
ER is making HLA class 2
HLA class 2 has an invariant chain blocking the peptide binding cleft
HLA 2 goes into endosome
Proteolytic enzymes degrade invariant chain so peptide binding cleft open
Antigen peptide binds to HLA class 2
Goes to cell surface
15
Q

Express antigen processing with HLA class 1 and Tc cells

A
Endogenous antigen
Proteosome takes antigen into cytosol
Broken into peptides
ER is making HLA class 1
Antigen peptides are taken to HLA class 1
They bind and go to the cell surface
16
Q

Define cytokines

A

Secreted proteins that help regulate cellular activity