Biology - Review Qns - 8

Question 1

How can Immunity develop?

Answer 1

Immunity can develop naturally or be induced artificially.

Question 2

What is passive immunity?

Answer 2

Passive immunity involves the transfer of antibodies produced in another organism. It does not result in immunological memory and is temporary.

Question 3

What is active immunity?

Answer 3

Active immunity involves the individual’s adaptive immune response. It results in immunological memory that can be long-lasting.

Question 4

How does passive immunity occur naturally?

Answer 4

Natural passive immunity is the result of antibodies naturally produced by another organism providing immunity, e.g. maternal antibodies transferred through the placenta and breast milk.

Question 5

How does artificial passive immunity occur?

Answer 5

Artificial passive immunity involves an individual receiving, usually by injection of antiserum, antibodies produced by another organism. The antibodies bind to antigens on the pathogen or toxin, preventing them from causing damage; but may also prevent the body’s own adaptive immune response, thereby preventing the development of immunological memory.

Question 6

How does active immunity develop naturally?

Answer 6

Natural active immunity develops from the adaptive immune response to a natural infection, and the immunological memory that results.

Question 7

What generates Artificial active immunity?

Answer 7

Artificial active immunity results from the administration of antigens to induce an adaptiveimmune response, i.e. vaccination. This results in the generation of immunological memory.

Question 8

What is immunological memory?

Answer 8

Immunological memory provides a stronger and faster secondary immune response if exposed to the same antigen again.

Question 9

What is a ‘Live Attenuated Vaccine’?

Answer 9

Live attenuated vaccines involve a living microbe that has been weakened in the laboratory, usually through repeated culturing.

Question 10

What is an ‘Inactive Vaccine’?

Answer 10

Inactivated (or killed) vaccines are composed of microbes inactivated by heat radiation or chemical means.

Question 11

What is a ‘Sub-unit vaccine?’

Answer 11

Subunit vaccines contain a fraction of an antigen, a single antigen or multiple antigens, and these antigens can be proteins, detoxified toxins or polysaccharides.

Question 12

What is a ‘Toxoid vaccine?’

Answer 12

Toxoid vaccines are non-recombinant subunit vaccines that use toxins inactivated by formalin (called toxoids).

Question 13

Why have vaccination programs?

Answer 13

Vaccination programs are set up by governments in an effort to produce herd immunity.

Question 14

What is ‘Herd Immunity’?

Answer 14

Herd immunity is the result of large numbers of people being immune to a pathogen, thus reducing the chance of the pathogen successfully spreading through a population.

Question 15

What are hypersensitivity reactions?

Answer 15

Hypersensitivity reactions occur when the immune system overreacts.

Question 16

What are the types of Hypersensitivity Reactions?

4 types

Answer 16

type I (or immediate) hypersensitivity, also known as allergy
type II (or cytotoxic) hypersensitivity
type III (or immune complex) hypersensitivity
type IV (or delayed-type) hypersensitivity

Question 17

What are allergens?

Answer 17

Antigens that trigger an allergic reaction are called allergens, and include pollens, dust, fur and foods.

Question 18

What do allergic reactions involve?

Answer 18

Allergic reactions involve the production of IgE, which attaches to the surface of mast cells. When an allergen cross-links two IgE molecules on a mast cell, it triggers a signal transduction cascade that results in the release of histamine.

Question 19

What is Histamine?

Answer 19

Histamine is a compound that dilates blood vessels, increasing their permeability and promoting inflammation.

Question 20

What is ‘Self Tolerance’?

Answer 20

Self-tolerance is the inability to recognise selfantigen.

Question 21

What causes Autoimmune disease?

Answer 21

Autoimmune diseases result from a failure of self-tolerance. leading to adaptive immune responses against self-antigens. Autoimmune diseases can be organ-specific or generalized.

Question 22

What types of reactions can

Answer 22

Autoimmune diseases can result in type II. type III and type IV hypersensitivity reactions.

type II = (or cytotoxic) hypersensitivity

type III = (or immune complex) hypersensitivity

type IV = (or delayed-type) hypersensitivity

Question 23

What is Multiple sclerosis?

Answer 23

Multiple sclerosis is an organ-specific autoimmune disease that affects the central nervous system.

Question 24

How does Multiple Sclerosis happen?

Answer 24

Both helper and cytotoxic T lymphocytes are involved in multiple sclerosis, and plasma cells produce antibodies against the proteins and lipids in the myelin sheath that insulates nerve cell axons.

Question 25

**What effect does Multiple Sclerosis have?**

Answer 25

The damage to the myelin sheath impairs the conduction of nerve impulses.

Question 26

**What is Immunodeficiency**

Answer 26

Immunodeficiency is when the immune system cannot adequately respond to antigens, or fails to react at all.

Question 27

**What types of Immunodeficiency are there?**

Answer 27

Immunodeficiency can be primary or secondary: * Primary immunodeficiency is congenital and examples include DiGeorge syndrome and SCID (bubble babies). * Secondary immunodeficiency is acquired and can be temporary (malnutrition) or permanent (AIDS).

Question 28

**What causes AIDS?**

Answer 28

AIDS results from untreated infection with HIV, a retrovirus that has such a high rate of mutation that it evolves and evades the immune system.

Question 29

**How does HIV make you sick?**

Answer 29

Over time the virus impairs the adaptive immune response by reducing the number of helper T lymphocytes, making infected people susceptible to opportunistic infections and certain types of cancers.

Question 30

**How does cancer occur?**

Answer 30

Cancer occurs when a single rogue (or abnormal) cell multiplies uncontrollably and spreads throughout the body.

Question 31

**What cancer treatments are in use?**

Answer 31

Cancer treatments over the last several decades have included: * Chemotherapy * Radiation therapy * Surgery. These treatments come with significant side effects.

Question 32

**What is Immunotherapy?**

Answer 32

Immunotherapy is any treatment that harnesses the immune system of the patient to fight diseases such as cancer.

Question 33

**What types of Immunotherapies are used?**

Answer 33

Immunotherapies can be non-specific, such as the injection of cytokines, or specific, such as cancer vaccines, personalized immunotherapy or monoclonal antibody therapy.

Question 34

**What are cancer vaccines?**

Answer 34

Cancer vaccines are made using specific antigens from cancer cells or infectious agents that cause cancer. Like other vaccines, they are administered to a patient to stimulate an immune response that results in the production of an immunological memory.

Question 35

**Where are preventative cancer vaccines used?**

Answer 35

Preventative cancer vaccines are directed at viruses that cause cancer such as human papillomavirus (HPV). which causes cervical cancer. Antigens specific to the virus are injected into the body, triggering an adaptive immune response that will lead to immunological memory.

Question 36

**Where are therapeutic cancer vaccines used?**

Answer 36

Therapeutic cancer vaccines are made up of antigens for a specific type of cancer. These antigens are injected into the body along with adjuvants that help boost the immune response.

Question 37

**Where are personalised cancer vaccines used?**

Answer 37

Personalised cancer vaccines involve cells or substances from the patient, which are removed, altered in a laboratory and then reintroduced by injection. The most effective personalised immunotherapies involve the patient's own tumour and dendritic cells.

Question 38

**What is Monoclonal antibody (mAb) therapy?**

Answer 38

Monoclonal antibody (mAb) therapy involves antibodies produced by a single clone of B lymphocytes that are replicated in culture. mAbs are all identical and specific to the same antigen. Targeting specific cells reduces harm to healthy cells, but identifying the specific antigen in order to create mAbs is a difficult task.

Question 39

**What were the 1st mAbs**

Answer 39

The first monoclonal antibodies (mAbs) were mouse mAbs made entirely by mouse B lymphocytes.

Question 40

**How is immune response to mAbs avoided?**

Answer 40

To avoid an immune response against mAbs. chimeric, humanised and human monoclonal antibodies can now be produced using transgenic mice: • Chimeric mAbs are a mix of human and mouse components. • Humanised mAbs are also a mix but are mostly human. • Human mAbs are fully human.

Question 41

**What are conjugated mAbs?**

Answer 41

mAbs can be used as carriers of treatments (drugs, toxins and radioactive particles) for delivery specifically to cancer cells. These types of mAbs are called conjugated mAbs.

Question 42

**What are Bispecific mAbs?**

Answer 42

Bispecific mAbs are made up of two different mAbs and have two different binding sites: one is usually for a cancer cell and the other for an immune cell, such as a T lymphocyte. This enables an 'identify' and 'deliver' approach.