Co-ordinating Immune Response

Question 1

Describe the changes in microorganism levels following the duration of an infection

Answer 1

Question 2

Describe the histological structure of healthy skin

Answer 2

Question 3

Describe the basic structure of a lymph node, with reference to the T cell area and B cell area

Answer 3

Question 4

What happens to skin following inflammatory response?

Answer 4

Question 5

In initial immune response which complement pathways are activated?

Answer 5

• Alternate or Lectin but not classical

Question 6

What happens when a phagocyte comes into contact with a bacteria?

Answer 6

1. Bacterial binding to endocytic receptors of macrophages induce their engulfment and degradation.
2. Bacterial components binding to signaling receptors of macrophages induce the synthesis of inflammatory cytokines.

Question 7

What are the consequences of cytokine influence on the surrounding vasculature?

Answer 7

Question 8

Where do phagocytic cells come from?

Answer 8

• Neutrophils travel to and enter the infected tissue, where they engulf and kill bacteria. The neutrophils die in the tissue and are engulfed and degraded by macrophages.

Question 9

Describe cellular traffic in the lymph node draining an infection

Answer 9

• Information transmitted via afferent lymphatic vessels.

- Leave through efferent lymphatics.

Question 10

Explain the role of dendritic cells in T cell responses..

Answer 10

- Specialised dendritic cells are required to turn on T cell responses

• They can capture and process antigen
• They can migrate from peripheral tissues
• They have MHC Classs II molecules

- They can provide ‘costimulation’ - a second signal required to activate T cells

Dendritic cells can also sense the environment:

- They have a range of PRR, including TLRs

• They make a range of cytokines to influence T cell differentiation

Question 11

What is the process by which T cells enter the lymph node and generate into effector cells?

Answer 11

• T cells enter lymph node across high endothelial venules in the cortex.
• T cells monitor antigen presented by macrophages and dendritic cells.
• T cells that do not encounter specific antigen leave lymph nodes through lymphatics.
• T cells that encounter specific antigen proliferate and differentiate into effector cells.

Question 12

How are naieve T cells stimulated?

Answer 12

Question 13

Why do we get swollen lymph nodes?

Answer 13

Question 14

How are Th1 and Th2 cells created?

Answer 14

Question 15

How are CD8, CD4 cells created?

Answer 15

Question 16

How are B cells created?

Answer 16

1. Recirculating B cells enter lymphoid organs through high endothelial venules and migrate to the primary follicle.
2. Antigen-specific B cells are trapped at the border between the T zone and the follice.
3. Proliferating B cells form a primary focus: some B cells migrate to medullary cords and secrete antibodies.
4. Several B cells migrate into a nearby follicle forming a germinal center where rapid proliferation and somatic mutation can occur.
5. Somatically mutated B cells that retain the capacity to bind antigen, survive, whilst other B cells, die.

Question 17

Label the germinal centres of a lymph node

Answer 17

Question 18

How do B cells die?

Answer 18

Question 19

When do most T effector cells die?

Answer 19