11.1 Antibody Production & Vaccination

This image shows a type of phagocyte called a neutrophil.

• N1-N4: multi-lobed nucleus
• A: Lysosomes
• G: glycogen granules

Use the image to explain how neutrophils are adapted for their role.

When pathogens enter the body, phagocytes carry out a process called phagocytosis, which is a non-specific response.

Outline the process of phagocytosis and explain how it eventually leads to a specific immune response in the infected individual.

Antigens associated with allergens such as pollen or food substances can trigger both specific and non-specific immune processes.

One such process is the release of histamines in response to activation of B-lymphocytes.

Justify, with a reason, which part of this process constitutes a specific immune response.

Explain how the histamines released during an allergic reaction may assist phagocytes in their role.

The graph below shows the events that take place during the progression of a vaccination program

Suggest an explanation for the events seen in stage 3 of the vaccination program.

Towards the end of stage 4 in the graph from part a), the disease incidence drops to zero.

Explain what needs to happen within the vaccination programme to reach a disease incidence of zero.

The table shows the herd immunity thresholds for several different diseases.

Of the diseases listed, only smallpox has been fully eradicated.

Use the information in the table and your own knowledge to explain why.

In the 1850's a law was passed in the UK to make vaccination against smallpox compulsory in infants.

At this time, there was an estimated population of 27 368 800 and the birth rate was 35 live births per 1000 people.

Calculate how many babies needed to be vaccinated to reach the herd immunity threshold suggested in part c).

The image shows the evolutionary links between the simian immunodefficiency virus (SIV) and the human immunodefficiency virus (HIV).

Note that the image shows the evolution of two strains of SIV, one in chimpanzees (cpzPtt) and one in gorillas (gor).

Suggest what the image indicates about the emergence of HIV in human populations.

The image shows some of the changes that take place in the blood after infection by HIV.

After 2 years since infection, HIV leads to the development of Acquired Immunodeficiency Syndrome (AIDS).

Use the information in the graph and your knowledge of the immune system to explain this.

HIV infects human T-cells by binding to a cell surface receptor called CD4. This binding causes a shape change in the viral surface glycoproteins, enabling the virus to enter the host cell.

A new treatment for HIV involves a monoclonal antibody called Ibalizumab, the action of which is shown in the diagram below.

Suggest how Ibalizumab works as a treatment for HIV

A trial looking at the efficacy of Ibalizumab investigated its impact on CD4 cell (also known as helper T cell) count after 25 weeks of treatment.

The results are shown in the graph and include the standard deviations for each group of patients.

State and explain what can be concluded about the efficacy of Ibalizumab from the results shown.

One mark is available for clarity of communication throughout this question.

Describe and explain the changes that take place to the cell ultrastructure of a B-cell after activation to ensure it is adapted for its function.

Outline the process which occurs in a pregnancy test to give a positive test result.

Discuss the benefits and risks associated with vaccination programmes.

A medical researcher vaccinated a group of adult patients against human papillomavirus (HPV). He gave each patient two doses of vaccine five months apart. The researcher tested three samples of blood from each of the patients for antibodies against HPV.

Sample 1: taken 3 week before the first dose of vaccine

Sample 2: taken 3 weeks after the first dose of vaccine

Sample 3: taken 3 weeks after the second dose of vaccine

The results are shown in the graph below.

Calculate the percentage increase in the mean concentration of antibodies in the blood between samples 2 and 3.

In a trial for a new, improved version of the vaccine in part a), a doctor gave the new vaccine to a group of adult volunteers, following the same procedures.

Suggest two factors the doctor should have considered when selecting adult volunteers for this trial.

Explain the differences in antibody concentration between the three blood samples in the graph in part a).

The graph below shows the events that take place during the progression of a vaccination programme.

 

Suggest what the ‘adverse events’ labelled in the graph might be. 

Reaching the end of stage 5 in the graph in part a) is rare, and has so far only been accomplished for smallpox. 

Outline why it has not been possible to complete stage 5 for any diseases other than smallpox.

The smallpox vaccine was developed by Edward Jenner after he inoculated 9-year-old James Phipps with cowpox virus.

Explain how James Phipps developed plasma cells in response to the cowpox inoculation.

The graph below shows James Phipps’ antibody production in response to inoculation with cowpox.                         

Sketch a curve on the graph to show his antibody production in response to later inoculation with smallpox.

SARS-CoV-2 is the virus that causes COVID-19. The image below shows the structure of a rapid test strip used to test for the presence of SARS-CoV-2 antigens in a person’s nose and throat cells.

Describe what would happen in the region labelled ‘conjugate pad’ if an individual infected with SARS-CoV-2 placed a sample on the sample pad.

Explain how the sample mentioned in part a) would give a positive result on the test line.

State the function of the control line on the test shown in part a).

Several vaccines have been developed against SARS-CoV-2. One of the vaccines contains genetic material that allows an individual’s cells to synthesis SARS-CoV-2 antigens.

Suggest how this vaccine initiates the specific immune response against SARS-CoV-2.

One mark is available for clarity of communication throughout this question.

Explain the role of histamines in an allergic response.

Describe how tumour cells can be used in the production of monoclonal antibodies.

Explain how antibodies combat infection.