Immunity: Antibody Development and Short Term Immunity

If a sheep is injected with the box jellyfish venom on more than one occasion a higher yield of antivenom is obtained. Explain why.

T-memory cells and B-memory cells are stimulated as they recognise the antigen

Inducing a secondary immune response

With complementary antivenom produced much faster in greater numbers

Why does injecting antivenin not give a person lasting protection?

As it is passive immunity

Therefore no memory cells are produced

Once the antivenom is broken down, no further antivenom is produced by the individual

Suggest one problem in injecting antivenom produced by injecting sheep with venom and extracting antibodies from the sheep's blood?

Antigens and disease from the sheep may be transferred

(also may cause allergy

may cause immune response)

What is an antibody?

An antibody is protein, with a specific, complementary shape to an antigen.

Describe how antibodies are produced following a viral infection?

1. The virus contains antigens

2. The antigens proteins stimulate phagocytes to engulf and digest the pathogen

3. Macrophage phagocytes combine the antigen with MHC and display the antigen on the cell-surface

4. This stimulates T-helper cells to bind causing the macrophage to produce interleukin-1, which stimulates the T-helper cell to produce interleukin-2 which stimulates the T-helper cell to divide by mitosis forming clones which produce cytokines

5. The cytokines stimulate B-lymphocytes that are specific to the antigen to replicate by mitosis producing clones, known as clonal selection.

6. Some B-lymphocytes develop into plasma cells (some into memory B-cell) which produce a specific antibody with a complementary shape to the antigen.

(Describe how the antibody gene could be isolated from an animal cell and introduced into a crop plant e.g. maize?)

A DNA probe can be used to identify the antibody gene

Transcription enzyme can be used to cut the gene

at specific base pairs

Leaving unpaired bases

The same enzyme is used to remove the gene from the maize

DNA ligase is used to join the DNA

The recombined DNA is introduced into the maize plant

Explain why takin a course of antibodies from plants to treat herpes would not produce long-term protection against disease?

This is passive immunity

Therefore no memory B or T cells are produced

The antibodies are broken down and cannot be replaced

Explain one advantage of using antibodies from plants to treat a disease rather than from experimental animals?

Decreased risk of infection

Fewer ethical issues

Give two adaptations that epithelial cells have for the absorption of food?

1. Microvilli to increase surface area

2. Many mitochondria to release energy in respiration for use in active transport

(3. Carrier proteins/co-transporter proteins).

What is an antigen?

A protein on the surface of a pathogen that induces an immune response

Microfold cells take up the antigens and transport them to cells of the immune system. Suggest two reasons why antigens are not able to pass through the cell-surface membranes of other epithelial cells?

Too large

Not lipid soluble

There are no transporter proteins such as carrier/channel proteins with a complementary shape to the antigen

How would developing a vaccine that makes of the microfold cells lead to a person developing immunity to a pathogen?

1. Vaccine contains antigen as a dead or attenuated pathogen

2. The microfold cells bind (and present) and transport the antigen to the immune system

3. Antigen presentation stimulates T-helper cells

4. Which produce cytokines which produce T-memory cells and activate specific, complementary shaped B-cells

5. to divide by mitosis forming clones (clonal selection)

6. B-cells develop into plasma B-cells which produce antibodies with a complementary shape to the antigen

7. In addition to B-memory cells

8. When reinfected; the memory cells produce more antibodies, faster, in a secondary immune response.