Lecture 1 - Overview

Question 1

How and when did Edward Jenner develop the first vaccination??

Answer 1

In 1796, noticed milk maids fair skin, pustules on hands from unfatal cow pox, infected boy with cow pox, boy survived, cow pox conferred protection against fatal small pox

Question 2

What is a commensal organism?

Answer 2

Where one organism benefits and the other is unaffected

Question 3

What is a mutualism?

Answer 3

Where both organisms benefit

Question 4

What is a parasitism?

Answer 4

Where one organism benefits at the expense of the other

Question 5

Most bacteria are… commensal mutual or parasites?

Answer 5

Most bacteria are commensal

Question 6

Where do bacteria play an important role in the body?

Answer 6

fermentation, digestion, absorption or nutrients

Question 7

What are pathogens?

Answer 7

Organisms that cause disease; virus, bacteria, fungus, parasites

Question 8

What are the three barries your body has to protect against infection?

Answer 8

1) Mucosal barriers 2) Innate immune system 3) Adaptive immune system

Question 9

What are the bodies mucosal barriers?

Answer 9

Skin 2m, Respiratory tract 120m, Intestines 200m

Question 10

What are features of the innate immune system?

Answer 10

1) Immediate and act within minutes
2) recognise foreign pathogens via germline encoded receptors
3) No memory

Question 11

What are features of the adaptive immune system?

Answer 11

1) days to develop
2) highly specific, requires sophisticated rearrangement of receptor genes
3) generates memory

Question 12

Define Haematopoiesis

Answer 12

the development of blood cells from stem cells in the bone marrow (haematopoietic stem cells)

Question 13

What are the two lineages that derive from the haematopoetic stem cell in the bone marrow?

Answer 13

Lympoid lineage and the Myeloid lineage

Question 14

What cells derive from the Lymphoid lineage?

Answer 14

B lymphocyte, T lymphocyte, NK cells

Question 15

What cells derive from the Myeloid lineage?

Answer 15

Granulocyte (macrophage progenitor) from which the granulocytes [neutrophils, eosinophils, basophils] , monocytes [dendritic cells, macrophages] and unknown mast cell progentior [mast cell] develop. ALSO MEGAKARYOCYTES AND RBC

Question 16

What are the 4 major immunological tissues?

Answer 16

1)Bone marrow [haematopoietic stem cells come from]
2) Thymus [T cells develop]
3) Spleen [immune responses]
4] lymph node and peyers patch [secondary lymphoid tissue]

Question 17

What are the three types of phagocytes?

Answer 17

1) Macrophages
2) Granulocytes
3) Dendritic cells

Question 18

What are the features of the phagocytic cells?

Answer 18

• detect ‘particulate’ material and seek to remove
  2) aided by limited number of receptors which recognise broad molecular patterns not present in eukaryotes
  3) Do not vary

Question 19

What is the function of macrophages?

Answer 19

• phagocytosis (antigens, pathogens and bacteria) and activation of bacterial mechanisms
• trigger the release of factors e.g. chemokines and cytokines, recruit neutrophils
• induce inflammation

Question 20

Who discovered macrophages and how?

Answer 20

Llya Ilyich Mechnikov (late 1800s)

Stuck thorns into starfish (no adaptive only innate) to discover macrophages

Question 21

Where are macrophages found?

Answer 21

In all peripheral tissues

Question 22

What are the functions of neutrophils?

Answer 22

• phagocytise (ingest and kill bacteria)
• activate bacterial mechanisms
• recruited by macrophages, migrate rapidly from site of infection
• release granules that contain toxic components

Question 23

What happens when neutrophils invade the site of infection?

Answer 23

1) Bacteria trigger macrophages to release cytokines + chemokines
2) Proteins and fluids move out of the blood vessel into site of infection (redness and swelling)
3) Inflammatory cells (neutrophils) migrate into tissue releasing further inflammatory mediators

Question 24

How can we visualise the invasion of neutophils into a s.o.i?

Answer 24

Neutrophils express GFP

Question 25

What occurs when neutrophils die?

Answer 25

collect into a white pus containing dead cells and neutrophils

Question 26

What is the general pathway of the innate immune system?

Answer 26

1) activation of tissue macrophages 2) phagocytation and attraction of neutrophils 3) influx of neutrophils leads to localised inflammation, redness, heat and pain

Question 27

What are B cells and what are their features?

Answer 27

- speicialised form of lymphocyte - express antigen specific receptors - produce soluble or membrane bound antibodies which recognise 3d shape of an antigen, the eptiope on surface of antigen (mostly anything)

Question 28

What are the two types of T cells and what are their features?

Answer 28

1 - Killer T cell (cytotoxic T cell) 2 - T helper cells - help B cells make antidbodies -express T cell receptors only recognise peptides

Question 29

What is the structure of an antibody?

Answer 29

2 variable regions (antigen binding site) a constant region (effector function- 2 light chains and 2 heavy chains (joined by disulphide bond)

Question 30

What is the T cell receptor structure?

Answer 30

- alpha and beta variable region (antigen binding site) | - constant region

Question 31

What is an antigen

Answer 31

any molecule capable of being recognised by an antibody or T cell receptor

Question 32

What is the general peptide presentating process in T cells?

Answer 32

1) Antigen broken down into peptide fragments 2) epitope peptide binds to MHC molecule 3) T cell receptor binds to complex of MHC and epitope peptide

Question 33

What are dendritic cells and what are their features?

Answer 33

Dendritic cells are phagocytic cells that degrade pathogens - for activation immune response - characterised by long dendritic processes - migrate from peripheral tissue to lymph node and initiate AIR - actively survey peripheral tissues - actively transport antigen from s.o.i to lymph node

Question 34

Who discovered dendritic cells?

Answer 34

Ralph Steinman

Question 35

How are dendritic cells transported from s.o.i. to lymph node?

Answer 35

Through the lymphatic vessel network lymphatic capillaries to transport, drain into local lymph nodes, back into circulation through the subclavian vein

Question 36

What is the importance of the lymphatic vessel network?

Answer 36

- allows migration network for dendritic cells and lymphocytes - allows fluid drainage from peripheral tissues

Question 37

What is Elephantiasis?

Answer 37

condition where lymph nodes are blocked leading to lymphodema

Question 38

Where are lymph nodes found?

Answer 38

at drainage sites in the lymphatic vessel network

Question 39

What are afferent lymphatic vessels?

Answer 39

Those collecting into a lymph node

Question 40

What are efferent lymphatic vessels?

Answer 40

Those leaving lymph nodes

Question 41

What are lymph nodes?

Answer 41

Highly specialised organised tissues with specific functions for each area e.g. the B cell follicle (antibody response generated) and the T cell paracortex (interaction of T cells and dendritic cells, T helper cells help to make antibody)

Question 42

What is sepsis?

Answer 42

Where severe bacterial infection within the blood

Question 43

What organ prevents sepsis and how?

Answer 43

SPLEEN - 95% blood filters though 3 mins - Removes damaged RBC - Removes bacteria, white pulp regions where immune cells reside, organismed to respond and pick up pathogens and filter blood out

Question 44

What is the difference between primary and secondary lymphoid tissue?

Answer 44

Primary - where immune cells develop | Secondary - Where immune response occurs (lymph node, pyrus patch and spleen)