lecture 19 - immunology

Question 1

innate immunity =

Answer 1

recognition of obvious traits shared by a broad range of pathogens. very rapid response, however, if it is new and changing bacteria, you will not be able to identify it. e.g. neutrophils and macrophages

Question 2

adaptive immunity =

Answer 2

recognition of specific pathogen traits, using a vast array of receptors. slower response and only occurs in vertebrates. Includes both humoral response and cell-mediated response.

Question 3

humoral response

Answer 3

antibodies defend against infection in body fluids

Question 4

how many lymphocytes renewed each day?

Answer 4

10^9

Question 5

lymph nodes

Answer 5

mosaics of B-cell and t-cell clones. Lymph travels through them before re-entering the blood

Question 6

5 steps to immune response

Answer 6

1. immediate inflammatory response
2. specific t-helper activation
3. specific b-cell activation
4. b-cell clonal expansion
5. memory update

Question 7

trigger and cause of localised swelling at infection site (step 1)

Answer 7

triggered by tissue damage, caused by opening of capillary walls.

Question 8

mast cells

Answer 8

move to infection site, release histamine, which in turn attracts neutrophils.

Question 9

phagocytic cells involved in the immediate response

Answer 9

neutrophils (not an APC)

then, macrophages/dentritic cells (APC), B-cell (APC),

Question 10

how do leukocytes move out of blood vessels (not including arteries)?

Answer 10

cytokines released at site of inflammation, increase permeability to WBCs

Question 11

How leukocytes move through vessels

Answer 11

surface proteins called selectins form weak bonds with carbohydrates on the outside of the WBCs, which allow them to stick and roll slowly through.

Question 12

Antigen presenting cells (APC)

Answer 12

• phagocytosis of pathogen
• digestion of antigen to peptide fragments
• vesicle with fragments fuse to vesicle with MHC class 2 molecules
• fragments form complex with MHC class 2
• vesicle undergoes exocytosis and complex binds to membrane

Question 13

aproximate length of peptide antigen fragments

Answer 13

~10 amino acids

Question 14

alarm #1

Answer 14

dendritic/macrophage cells carry antigen peptides (on membrane) to the lymph nodes, and bind the T-cell clones with the specific TCR - stimulating them to divide.

Question 15

alarm #2

Answer 15

antigen presenting B-cells arrive at the lymph nodes. Activated T-cells bind to antigen and release interleukin 2 and cytokines, helping the B-cell differentiate. Activated B-cell clones produce huge number of antibodies.

Question 16

clonal expansion

Answer 16

process where lymphocyte clones divide

Question 17

auto-immune disease

Answer 17

antibodies bind to your own proteins

Question 18

T-helper cells function?

Answer 18

assist other cells produce more anti-bodies, OR stimulate formation of cells which can specifically destroy foreign or infected cells

Question 19

T-cell clones divide into…

Answer 19

memory T-helper cells (long lived) and T-helper clones

Question 20

B-cell clones divide into

Answer 20

plasma cells (antibody production) and memory B-cells (long lived)

Question 21

key features of B-cell clonal expansion

Answer 21

• delayed 1-2 weeks
• more effective and specific
• lymph nodes swollen
• huge antibody production
• t-cells still stimulating b-cell production

Question 22

what eventually happens by the end of the immune response

Answer 22

all bacteria are eventually tagged and killed by macrophages or b-cells

Question 23

first to develop a vaccine? for which disease?

Answer 23

Jenner. Vaccine for smallpox

Question 24

second infection features and reasons

Answer 24

rapid response, may not even be noticed that you were ever infected. This is due to increased antibody level in blood and there are now large clones of specific B and T cells in the lymph nodes.

Question 25

which cells have CD4 proteins?

Answer 25

macrophages and T-cells

Question 26

what do antibodies do?

Answer 26

tag pathogens for destruction

Question 27

chemicals released by T-helper cells, encouraging B-cell differentiation

Answer 27

interleukin 2 and cytokines

Question 28

allergies

Answer 28

Inappropriate or excessive immune responses to antigens

Question 29

cell-mediated response

Answer 29

Cytotoxic cells defend against infection in body cells.