Antibodies & Vaccination (CIE A Level Biology)

Fig. 1 shows the 3-dimensional structure of an IgG antibody.

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Fig. 1

[1]

Explain how antibodies such as that shown in Fig. 1 are adapted to their function.

Fig. 2 shows one way in which antibodies interact with pathogens.

Fig. 2

[1]

It is possible to engineer antibodies in the laboratory to carry out particular functions.

Suggest how an antibody could be engineered to carry out a specific function.

Monoclonal antibodies can be produced using a process known as the hybridoma method.

Outline how hybridomas can be used in the production of monoclonal antibodies.

Lymphocytes known as T regulatory cells, or Treg cells, can act to suppress the activity of the immune system. In cancer patients this can be a problem as it prevents the cells of the immune system from destroying tumour cells.

Suggest how monoclonal antibodies could be used to reduce the activity of Treg cells.

While part b) descibes a problem resulting from the activity of Treg cells, a lack of Treg cell activity can cause other problems.

Suggest why the activity of the Treg cells described in part b) is important.

Some breast cancers are caused by overexpression of a protein known as HER2. These types of breast cancers can be treated with a monoclonal antibody known as trastuzumab that targets HER2 proteins.

Fig.1 shows how monoclonal antibodies that target HER2 proteins can be produced.

Fig. 1

In Fig.1:

[1]

[1]

The monoclonal antibodies produced in Fig. 3.1 need to undergo a process known as humanisation before they can be used as a treatment for breast cancer in humans.

Suggest why the antibodies need to be humanised.

[2]

Fig. 2 shows the results of a study that compared rates of disease free survival in HER2-related breast cancer patients receiving either chemotherapy alone or chemotherapy alongside trastuzumab.

Fig. 2

Calculate the percentage increase in disease-free survival after 4 years in patients receiving chemotherapy alongside trastuzumab in comparison with patients receiving chemotherapy alone.

Other than survival rates, suggest why it is advantageous to use monoclonal antibodies in cancer treatment rather than traditional chemotherapy.

Fig. 1 shows the antibody concentration in the blood after the administration of a vaccine and after infection with the same pathogen some time later.

Fig. 1

Explain the differences in antibody concentration between that after administration of the vaccine and that after infection with the same pathogen.

Fig. 2 shows the number of measles cases in England and Wales between 1940 and 2010. The measles vaccine was introduced in 1968.

Fig. 2

Describe the trend shown in the data in Fig.2 for the years:

[2]

[2]

Despite the introduction of the measles vaccine, measles has not been eradicated.

Suggest three reasons why this is the case.

Contrast the immunity gained by children who are given the measles vaccine with the immunity that babies are born with.

Tetanus is a potentially life threatening infection caused by Clostridium tetani bacteria. Upon infection with C. tetani, a toxin is produced by the bacteria that results in painful muscle contractions. One method of treatment involves the injection of tetanus antitoxin, which contains antibodies derived from a person that was vaccinated against tetanus.

Fig.1 shows the concentration of antibodies in the bloodstream of two individuals, A and B. Person A was injected with tetanus antitoxin, while person B was vaccinated against tetanus.

Fig.1

Compare the antibody concentration of person A and B, with reference to Fig.1.

Identify the type of immunity that person A and B gained, as illustrated by Fig.1.

Person A and B each gained a different type of immunity against tetanus.

Explain the advantages of the type of immunity gained by person B.

With reference to Fig.1, suggest why the tetanus antitoxin is an effective form of treatment against tetanus.

Antibody molecules are proteins that show primary structure, secondary structure, tertiary structure and quaternary structure.

Fig.1 shows a ribbon diagram of an antibody molecule.

Describe how Fig.1 shows the secondary structure and tertiary structure of the antibody molecule.

Fig. 2 is a transmission electron micrograph of a hybridoma cell.

Fig. 2

The hybridoma cell in Fig. 2 synthesises and secretes molecules of a monoclonal antibody.

State the roles of the structures labelled X and Y in the production of antibody molecules in the hybridoma cell.

[2]

(ii)

The hybridoma method for the production of monoclonal antibodies involves a number of stages. One of these stages is the formation of hybridoma cells.

Outline the stage in which hybridoma cells are formed.

[3]

(iii)

Outline the use of monoclonal antibodies in the treatment of disease.

Fig. 1 is a photomicrograph of a cross-section of a tubular structure in the kidney made from epithelial cells.

A ruler has been included for scale. 

Fig. 1

The actual length of epithelial cell A along the line P–Q is 35 μm.

Calculate the magnification of the image shown in Fig.1. Write down the formula and use it to make your calculation. Show your working.

[2]

Some epithelial cells in the kidney release the protein vascular endothelial growth factor (VEGF). This protein is a cell signalling molecule that stimulates cell division in endothelial cells in blood vessels.

(i)

State what occurs during interphase to prepare a cell for division.

[2]

(ii)

Explain how a cell signalling molecule, such as VEGF, can lead to a response in a cell.

[2]

Uncontrolled cell division may result in a tumour. Tumour cells in the kidney respond to VEGF.

Kidney cancer can be treated with monoclonal antibodies. These monoclonal antibodies bind to VEGF.

Outline the hybridoma method for the production of monoclonal antibodies that will target the VEGF protein.

Monoclonal antibodies used as a treatment need to be given more than once. Repeated treatment can cause side effects to the person or can become less effective.

Suggest why repeated treatment with monoclonal antibodies may have these effects.

In the UK babies are routinely vaccinated against pathogens such as measles viruses and meningococcal group B bacteria. Babies are given two or three separate vaccinations against these diseases at regular intervals before their third birthdays.

Explain why more than one vaccination is offered for each disease.

Fig. 1 shows the incidence of invasive meningococcal disease in the UK from 2010 to 2020. The vaccine for meningococcal B infections was introduced to the UK in 2015.

Fig.1

[4]

Suggest a reason for the data shown in 2018/19.

[1]

Routine vaccination of babies ensures that as many people as possible are vaccinated. Suggest how this protects the UK population against pathogens such as measles viruses and meningococcal bacteria.

An expectant mother is concerned about the health of her unborn baby after she has been infected with a common influenza virus (the flu). Her doctor tells her there is no need to be concerned. 

Explain how a foetus is protected against the pathogens that infect its mother during pregnancy.