Adaptive Immunity: Effector Phase

Question 1

State the immune functions of;

IgM
IgG
IgE
IgA

Answer 1

IgA: Mucosal immunity

IgE: Helminth immunity, Mast cell degranulation

IgG: Phagocytosis, complement activation, neonatal immunity

IgM: Complement activation

Question 2

Describe how an Antibody response and Effector cell response are made to come about.

Include the following aspects;

• Microbes
• Macrophages
• APCs
• Naive and mature B cells
• Naive CD4 and CD8 cells
• T helper cells and CTLs

Answer 2

1. Microbes breach innate barriers, and are taken up by macrophages and APCs
2. Microbes activate Naive B cells-> Mature B cells
3. APCs activate Naive CD4 T cells-> T helper cells, activate naive CD8 cells-> CTLs
4. T helper cells cause Mature B cells to produce an antibody response
5. CTLs produce an effector cell response

Question 3

What are 3 components of a T cell receptor (TCR)?

What forms of antigen do they recognise?

(TCRs are ON a T cell)

Answer 3

• Alpha and beta chains bonded together
• CD3 complex
• Accessory molecule (CD4 or CD8)
• Recognise peptides displayed by MHC molecules

Question 4

Describe how APCs activate T lymphocytes via costimulation

Answer 4

• MHC class I or II peptides presented to TCR

- B7 molecule on APC presented to CD28 on T cell

Question 5

Describe the T Helper cell response, including the T helper cells produced and their functions

Answer 5

Naive CD4+ cells-> TH1, TH2, TH17 or Treg cells

TH1: Activates CD8 cells, Macrophages, and B cells

TH2: Activates B cells, Eosiniphils, and Mast cells

TH17: Activates neutrophils

Treg: Tolerance and Immunosuppression

(TH1 and TH2 can turn into each other)

Question 6

Which T Helper cells make up Cell mediated immunity and Humoral immunity

Answer 6

Cell mediated; (Bacteria, Viruses, Fungi)
- TH1 cells

Humoral; (Parasites, Worms)

• TH2
• TH17

Question 7

Describe the activation of Naive CD8 cells into Effector and Memory CD8 cells

Answer 7

• APCs stimulate naive CD8 cells-> Memory CD8 cells and Effector cells
• TH1 cells needed to activate Naive CD8-> Effector CD8 cells

Question 8

What are the 3 outcomes of B lymphocyte activation

Answer 8

1. Antibody production;

• IgM production is T Helper independent
• IgG, IgA, IgE production is T Helper dependent

2. Memory B cells made
3. Affinity maturation in antibody response

Question 9

Compare when to use Vaccination and Immunoglobulin therapies

Answer 9

Vaccination: Before infection

Immunoglobulin therapies: After infection