Treating Disease

What are monoclonal antibodies?

Polyclonal antibodies are naturally produced in an immune response. Different plasma cells secrete antibodies, resulting in a variety of different antibodies against a specific antigen.

the treatment of cancer and other diseases

drug screening

home pregnancy kits

scientific research.

Monoclonal antibodies (mAbs) are antibodies produced from clones of a single plasma cell and are therefore all identical. They have many important uses, such as:

Production of monoclonal antibodies

Large quantities of mAbs can be produced using mice or rabbits.

A specific antigen is injected into the animal, stimulating the production of plasma cells.

The plasma cells are removed from the animal and fused with cancerous myeloma cells from normal mice. These form immortal hybridoma cells, which can produce a single type of antibody indefinitely.

Exam question – monoclonal antibodies

Remember:

- Antigen injected into animal- Plasma cells produced- Plasma cell fused with myeloma (cancer)

cell- Hybridoma cell formed – multiplies quickly

and indefinitely to produce many identical antibodies (for the original antigen).

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Artificial immunity

Vaccines, lymphocytes and the secondary response

Primary Response

The first time a new antigen is encountered, it takes time for B- and T-cells to respond.

Antibodies are produced fairly slowly as plasma cells are produced by mitosis of B-cells.

Memory cells (B and T) remain in the blood for a period of time after the initial infection.

Secondary Response

The second time the antigen is encountered, there are already a number of memory cells present.

The immune response is quicker.

More antibodies are produced more quickly than in the primary response.

Immunological memory

Now try the questions on the back of the sheet.

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Influenza vaccines

New strains of the influenza virus are constantly emerging. This is because antigens displayed on the virus change due to mutation. This causes antigenic variation.

The government works with other organizations to identify current strains of influenza. An effective vaccine is developed each year.

Antigenic variation makes it hard to immunize a patient against the influenza virus for life with just a single vaccine.

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What is vaccination?

Vaccines stimulate the production of antibodies and memory cells against the target pathogen without causing illness.

Why don’t vaccines cause illness?

They may contain an inactivated form of the pathogen, killed by heat treatment (which leaves the immune-stimulating antigens intact).

They may contain an attenuated (less virulent) form of the pathogen.

They may contain isolated antigens, such as cell surface proteins, from the pathogen.

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The MMR controversy

In 1998, a scientific paper was published in the medical journal The Lancet, speculating that the MMR vaccine could cause autism.

The authors did not prove that this was the case but still recommended that doctors stop administering the MMR vaccine until more research was done.

The authors thought that the MMR vaccine could damage the bowel, allowing toxins that are normally destroyed in digestion to move into the blood. If these toxins travelled to the brain they might cause autism.

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The media’s role in the MMR controversy

Many studies have concluded that the MMR vaccine is safe and only a few studies claim that it isn’t. However, this was not reflected by the media coverage.

Should scientists be more careful about how they present their research or should the media be responsible for how they present controversial topics to society?

This mixed message caused confusion among the general public, leading to a drop in the number of children being given the combined vaccine.

The majority of coverage centred on the possibility of a link between the MMR vaccine and autism, while the government insisted that the vaccine was safe.