7. Immunity

Question 1

Define vaccination

Answer 1

A vaccine is a solution containing a dead, weakened or attenuated form the of the pathogen or antigen (or mRNA instructions to make an antigen).

Question 2

State what passive immunity means

Answer 2

Short term immunity, recieving antibodies from another source. No B memory cells are made.

Question 3

Describe what active immunity means

Answer 3

Producing own antibodies by the humoral immune response. This leads to B and T memory cells that remain and cause longer term immunity.

Question 4

Define a pandemic

Answer 4

A significant rise in the level of incidence of a disease globally

Question 5

Define an epidemic

Answer 5

A significant rise in the level of incidence of a disease in a population

Question 6

Define endemic

Answer 6

The normal level of incidence of a disease in a population.

Question 7

State the 8 strategies used to control the spread of a pathogen.

Answer 7

Identify pathogen
Identify method of transmission
Block modes of transmission
Quarantine
Protect health workers.
Treat with appropriate medicine (e.g. antibiotics or antivirals)
Design a specific medicine
Create a vaccine
*Be careful of context of the question.

Question 8

Define zoonosis

Answer 8

An infectious disease that is caused by a pathogen that has transferred from an animal to a human.

Question 9

State 2 reasons why diseases can re-emerge

Answer 9

Global travel
Insufficient vaccination
Evolution and mutation of the pathogen (antigenic drift or shift)

Question 10

An example of artifical active immunity is a …

Answer 10

vaccination

Question 11

An example of natural active immunity is..

Answer 11

infection of a pathogen causing the creation of your own antibodies and B memory cells

Question 12

An example of natural passive immunity is ..

Answer 12

transfer of antibodies in breastmilk or across the placenta

Question 13

An example of artificial passive immunity is ..

Answer 13

an antivenom or injection of antibodies. Including monoclonal antibodies

Question 14

An auto immune diseases is caused by …

Answer 14

when auto antibodies recognise self cells as foreign and attack them.

Question 15

Define an allergy..

Answer 15

inappropriate or exaggerated reaction of the immune system to an unimportant stimulus that leads to excessive inflammation.

involves the excessive release of histamine by mast cells causing exaggerated inflammation and mucus production.

Question 16

Mast cells release

Answer 16

histamine

Question 17

Histamine causes

Answer 17

vasodilation and increased permeability

Question 18

A secondary humoural immune response produces a …..

Answer 18

more rapid and higher concentration of antibody production

Question 19

In an allergic reaction Ig E antibodies have formed cross links to …

Answer 19

allergen and two antibodies

Question 20

Possible strategies to limit transmission of pathogens are

Answer 20

Quarantine, masks, gowns, gloves, close borders, educate, treat - vaccination, drug, RDD, remove vector

Question 21

Emergent diseases can be caused by

Answer 21

Antigenic shift and Zoonosis

Question 22

Monoclonal antibodies are …

Answer 22

are laboratory produced antibodies that can bind to a specific and complementary antigen on a cancer cell, usually administered by a drip.

Question 23

What is Herd immunity?

Answer 23

Herd immunityoccurs when a large portion of a community (normally more than 90%) becomes immune to a disease, making the spread of disease from person to person unlikely.

Herd immunity reduces the number of potential hosts.

Question 24

Disinfectants …

Answer 24

destroy pathogens on surfaces e.g. door, work top

Question 25

Antiseptics …

Answer 25

destroy pathogens on the body

Question 26

Antigenic shift is ….

Answer 26

Definition:
Sudden and significant mutations in the genes encoding for viral surface antigens

when the genetic material from two different viruses is accidentally combined within an infected cell creating a ‘new’ pathogen

Question 27

Why do diseases re-emerge?

Answer 27

Evolution and mutation of the pathogen

Globalisation and travel

Larger human population

Insufficient vaccination

Question 28

Immune deficiency is caused by …

Answer 28

malfunction or deficiency of one or more parts of the Immune System

Question 29

How are monoclonal antibodies made using a mouse.

Answer 29

Identify antigen on cancer cell

Vaccinate mouse with antige

Extract B cells

Fuse B cells with myeloma cells, to create hybridoma cells.
Myeloma cells are actually also cancerous plasma cells.

Selection of appropriate hybridomas
Collection and purification.

Question 30

Define re-emergence of a disease.

Answer 30

A disease that reappears after being absent in a population for a significant period of time.

Question 31

Define emergence of a disease

Answer 31

An infectious disease that is new to the human population, or that is rapidly increasing in incidence

Question 32

Describe the steps in making monoclonal antibodies using genetic engineered bacteria.

Answer 32

Identify antibody gene from selected hybridoma and use reverse transcriptase to get c.DNA
Cut gene and plasmid using the same endonuclease.
Stick gene into plasmid using DNA ligase which joins the sugar phosphate backbone.
Transform bacteria using heat or electrical shock
Check for successful transformation (usually using an antibiotic or GFP). Untransformed bacteria will die with the antibiotic. Successful will express the gene making the antibodies.
Collect and purify monoclonal antibodies

Question 33

Define antigenic drift

Answer 33

Small and gradual changes in the genes encoding viral antigens

Question 34

State the functions of monoclonal antibodies

Answer 34

Flag for phagocytosis by macrophages
Deliver toxic drug (if conjugated/loaded)
Activate natural killer cells
Activate complement proteins

Question 35

Describe the first step that occurs towards having an allergic reaction

Answer 35

Sensitisation. This means that IgE antibodies released from the humoral immune response attach to mast cells by their non variable region.

Question 36

Describe the second step towards an allergic reaction.

Answer 36

Degranulation. This means that after the allergen forms a cross link between two IgE antibodies attached to mast cells, histamine is excessively released from the mast cell.