innate and adaptive immunity

Question 1

complement pathway- cascade

Answer 1

classicical pathway- antigen:antibody complexes
mb-lectin pathway- lectin binding to pathogen surfaces
alternative pathway- pathogen surfaces

complement activation
- recruitment of inflammatory cells
- opsonisation of pathogens
- killing of pathogens

Question 2

complement

Answer 2

A cascade of proteins in serum
Activated by antibody, or molecules from pathogens
Amplifies the inflammatory response
Can directly kill pathogens, or attract immune cells

Question 3

neutrophils

Answer 3

50-60% of circulating leukocytes
short lived (6–12 hours)
First line of defence
several bacteriostatic and toxic factors.
phagocytose pathogens
release soluble mediators
- multi-lobed nucleus
phagosome fused with granules to destroy internalised bacteria, oxygen dependent respiratory burst

Question 4

innate cells migration to infection

Answer 4

1. rolling adhesion
2. tight biding
3. diapedesis
4. migration

Question 5

macrophages

Answer 5

Macrophages re-organise their actin cytoskeleton to engulf bacteria that are digested inside the cell.

Macrophages can also engulf apoptotic cells. The finger-like extensions that encapsulate the apoptotic cells are called pseudopodia

Question 6

adaptive immune system steps

Answer 6

1. pathogens infect tissues and activate innate cells
2. activated DCs move to lymphoid organs carrying the pathogen
3. DCs activate antigen specific CD4/CD8 T cells
4. cd4 T cells help B cells make antibody response
5. T cells migrate out of the lymph node
6. T cells migrate to infected tissues where they help innate cells kill the pathogens and antibodies aid clearance

Question 7

humoral adaptive immunity

Answer 7

Antibody mediated ‘extracellular attack’
Antibody from B cells
B cells mature in the bone marrow

Question 8

cell- mediated adaptive immunity

Answer 8

‘Cellular attack’
Due to T cells
T cells mature in the thymus

Mediated by T cells
Several components
Helper T cells – the managers of the immunological football team
Help B cells
Help cytotoxic T cells
Direct innate responses
Cytotoxic T cells

Question 9

types of T cells

Answer 9

CD4 - Th –T helper
Recognise antigen presented in MHC II on the surface of antigen presenting cells and ‘help’ them

CD8 - Tc – Cytotoxic T cells CTL
Recognise antigen presented in MHC I on many cell types and can be induced to kill

Question 10

helper t lymphocytes

Answer 10

“Help” the antigen-driven maturation of B and T cells
Facilitate and magnify the interaction between APCs and immunocompetent lymphocytes
Steps
Th interacts through antigen-specific and antigen-independent mechanisms
Undergoes differentiation
Mature Th interacts with plasma or T-effector cells