principles of immunology

Question 1

innate (nonspecific) immunity

Answer 1

response is antigen independent
there is immediate maximal response
not antigen specific
exposure results in no immunologic memory

Question 2

adaptive (specific) immunity

Answer 2

1. response is antigen dependant
2. there is a lag time between exposure and maximal response
3. antigen specific
4. exposure results in immunologic memory

Question 3

the innate systems physico-chemical barriers to infections

Answer 3

Skin, GI tract, Lung, Nasopharynx and eye, Circulation and lymphoid organs, serum

Question 4

cellular barriers to infection

Answer 4

part of the inflammatory response - recruitment of innate cells to sites of infection.
The main line of defence in the non-specific immune system
-neutrophils-(Polymorphonuclear cells) recruited to the site of infection and phagocytose invading organisms
-monocytes and macrophages - phagocytosis of microorganisms. Capable of extracellular killing of infected/altered self target cells. Contribute to tissue repair and act as antigen presenting cells.
-natural killer and lymphokine activated killer cell- kill virus infected and tumour cells (not part of the inflammatory response)
-Eosinophils- contain proteins in granules that are effective in killing certain parasites

Question 5

steps producing inflamation

Answer 5

1. a break in the skin introduces bacteria which reproduce at the wound site. activated resident macrophages engulf the pathogens and secrete cytokines and chemotaxins.
2. activated mast cells release histamine.
3. Histamine dilates local blood vessels and widens capillary pores. The cytokines cause neutrophils and monocytes to stick to the blood vessel wall.
4. Chemotaxins attract neutrophils and monocytes which squeeze out between cells of the blood vessel wall, a process called diapedesis, and migrate to the infection site.
5. Monocytes enlarge into macrophages. Newly arriving macrophages and neutrophils engulf the pathogens and destroy them.

Question 6

patterns recognised by innate system

Answer 6

• Components of innate immune system recognise broad molecular patterns (found on pathogens)
• patterns called PAMP (pathogen associated molecular patterns)
• Cells of innate system have PRRs on surface (pattern recognition receptors)
• PRRs can recognise a variety of different pathogens

Question 7

antigen presenting cells

Answer 7

belong to the innate system
Phagocytic cells
include: macrophages, dendritic cells

Question 8

the lymphoid system

Answer 8

lymphocytes arise from stem cells in the bone marrow and differentiate in the central lymphoid organs.
B cells- bone marrow
T cells- Thymus
Migrate from these tissues through bloodstream to the peripheral lymphoid tissues
Peripheral lymphoid tissues are sites of lymphocyte activation by antigen
Lymph- extracellular fluid from the peripheral tissues carries antigen to the lymph nodes and recirculating lymphocytes from the lymph nodes back into the blood