07. Immunity

Question 1

Describe natural active immunity

Answer 1

Individual contracts pathogen without medical intervention. This means that the humoral immune response is initiated, and the person eventually makes their own specific and free-floating antibodies and develops an immunological memory of this pathogen.

Question 2

Describe natural passive immunity

Answer 2

Baby receives specific complementary and free-floating antibodies from their mother by breast feeding or the placenta. This means that the baby has no immunological memory.

Question 3

Describe artificial passive immunity

Answer 3

Person receives specific complementary and free-floating antibodies by medical intervention (e.g. anti toxin). This means that the person has no immunological memory.

Question 4

Describe artificial active immunity

Answer 4

Individual contracts pathogen with medical intervention. This means that the humoral immune response is initiated, and the person eventually makes their own specific and free-floating antibodies and develops an immunological memory of this pathogen.

Question 5

Define a vaccine

Answer 5

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

Question 6

Define herd immunity

Answer 6

Herd immunityis 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 as there are less potential hosts.

Question 7

Define emerging disease

Answer 7

An infectious disease that is new to the human population.

Question 8

Define re-emerging disease

Answer 8

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

Question 9

Endemic

Answer 9

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

Question 10

Epidemic

Answer 10

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

Question 11

Define pandemic

Answer 11

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

Question 12

Define antigenic drift

Answer 12

Small and gradual mutations in the genes encoding for viral surface antigens

Question 13

Define antigenic shift

Answer 13

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

Question 14

Give 5 methods of disease transmission

Answer 14

Airborne, aerosol, direct physical contact, indirect physical contact and faecal-oral transmission

Question 15

Outline the steps in making monoclonal antibodies

Answer 15

Identify antigen on desired cell (e.g. cancer cell or autoimmune disease causing B cell)
Vaccinate a mouse with the desired antigen- mouse will select specific and complimentary B cells to the antigen
B cells are extracted
Fuse mouse B cells with a myeloma cancerous cell to produce a hybridoma
Select appropriate hybridoma
Monoclonal antibodies are collected and purified

Question 16

Define a monoclonal antibody

Answer 16

Monoclonal antibodies (mAb) are laboratory produced antibodies that can bind to specific and complementary antigens on a cell.

Question 17

Define allergen

Answer 17

Allergens are antigens that the immune system recognises as non-self and initiates a strong immune response towards.

Question 18

Describe an allergic reaction.

Answer 18

Allergies are inappropriate or exaggerated reactions of the immune system to unimportant stimuli, an allergen. This means that there is an excessive release of histamine by mast cells causing exaggerated inflammation and mucus production.

Question 19

State the two steps to allergies occurring

Answer 19

Sensitisation
Degranulation

Question 20

Describe the two steps to allergies occurring

Answer 20

Sensitisation. This means that after the humoral immune response in response to the allergen, specific complementary and free floating IgE antibodies are made and some of these IgE antibodies will bind to mast cells by their non-variable region in the connective tissue.

Degranulation. This means that on secondary exposure to the same allergen it attaches to the specific and complementary antigen binding sites on IgE on the mast cells forming a cross link which leads to excessive release of histamine, excessive mucus production and contraction of smooth muscle in the airways.

Question 21

State what medicine could be given to treat a bacteria infection

Answer 21

Antibiotics (these often break down the peptidoglycan cell wall)

Question 22

State what medicine could be given to treat a viral infection

Answer 22

Antivirals (these are enzyme inhibitors)

Question 23

Outline the different types of monoclonal antibodies

Answer 23

Conjugated monoclonal antibodies have a toxic drug attached to them to deliver them directly to the cell.
Bispecific monoclonal antibodies have 2 different antigen binding sites
Humanized monoclonal antibodies which have part mouse and part human protein as they are often made in mice anyway .

Question 24

Describe how a monoclonal antibody works

Answer 24

Monoclonal antibodies are designed to have antigen binding sites that are specific and complimentary to a particular ____antigen . They attach to the antigen.

This means that they will flag for phagocytosis by macrophages/
Activate complement proteins/
Activate natural killer cells/
Deliver toxic drug if conjugated – This reduces chemotherapy effects on healthy cells as it will bind directly to cancer cells

Question 25

State the two types of diseases which monoclonal antibodies can be designed to target

Answer 25

Autoimmune and cancer