b cells vaccine

Question 1

Describe how B-lymphocytes respond when they are stimulated by antigens.

Answer 1

divide by mitosis / form clones;
produce plasma cells;
(plasma cells) make antibodies;
(plasma cells) produce memory cells;

Question 2

vaccine

Answer 2

Injection of antigens / toxoids;

(Antigen from) attenuated microorganism / non-virulent
microorganisms / dead

microorganisms / isolated from microorganism;

Stimulates the formation of memory cells;

Question 3

what is a antigen

Answer 3

Foreign protein;

Accept glycoprotein / glycolipid / polysaccharide

2. (that) stimulates an immune response / production of antibody;

Question 4

what is a antibody

Answer 4

A protein / immunoglobulin specific to an antigen;

2. Produced by B cells

OR

Secreted by plasma cells;

Question 5

Explain the differences between the mean concentrations of antibodies in blood samples 1, 2 and 3.

Poliomyelitis is an infection caused by a virus.

A doctor vaccinated a group of patients against poliomyelitis. He gave each patient two doses of vaccine, 3 months apart.

An immunologist tested three samples of blood from each of the patients:

• (sample 1) taken 2 weeks before the first dose of vaccine(no antibodies
• (sample 2) taken 2 weeks after the first dose of vaccine(small amount of antibodies
• (sample 3) taken 2 weeks after the second dose of vaccine.(lots of antibodies

He measured the concentration of antibodies against the poliomyelitis virus in the patients’ blood each time. The results are shown in the graph.

Answer 5

Sample 1 / before vaccination no antibody released because patients not yet encountered vaccine / antigen / virus;

Accept ‘produced’ for ‘released’

2. (Sample 2 / primary response / after first dose) activation / clonal selection / expansion of B cells into plasma cells;
3. Plasma cells release antibodies;
4. (Sample 3 / secondary response / after second dose) memory cells produce more antibodies / produce antibodies more quickly;

Question 6

(i) People given whole-cell vaccines were more likely to develop harmful side effects than the people given the vaccines containing parts of the bacterial cells (lines 4–6).

Suggest reasons why.

_______________________

Answer 6

Heat(ing) supposed to kill bacteria;

2. Some might be alive / active / viable;

Accept active pathogens present

3. (If so) bacteria could reproduce;
4. Bacterium makes or contains toxin;
5. Toxin might not be affected / all destroyed by heat;
6. Bacteria or toxins attacking / killing person’s cells;

Question 7

People given whole-cell vaccines produced a greater range of antibodies against the bacterium than the people given the vaccines containing parts of the bacterial cells (lines 7–8).

Explain why.

___________

Answer 7

(Contains) many different / greater range of antigens;

2. Each antigen causes its own immune response / production of / has a specific (type of) antibody;

Question 8

The scientists concluded from their test that 4% of patients with long-term coughs actually had whooping cough (line 15).

Explain how they used the results of their test to reach this conclusion.

Answer 8

Only patients who had whooping cough have toxin / antibody /
immune response;

Accept converse e.g. those without antibody had another disease

2. Toxin is an antigen and is (only) produced by this bacterium;
3. Leading to presence of specific antibody / only 4% had this antibody / 13% did not have antibody;

Question 9

Suggest an explanation for the large increase in the number of deaths from influenza in year 11. after decreasing for a long time

Answer 9

mutation of virus / new strain;
mutant form not recognised by memory cells (allow antibodies);

Question 10

Haemagglutinin and neuraminidase are protein molecules. Haemagglutinin binds to receptor molecules on the surface of epithelial cells in the breathing system.
Neuraminidase is an enzyme which breaks down molecules in the surface membrane of epithelial cells and allows the viruses to be released from the cells.

(i) Describe how T lymphocytes recognise and respond to the influenza viru

Answer 10

T lymphocyte receptors recognise shape of haemagglutinin /
neuraminidase / viral antigen;
clone (once only);
destroy virus;

Question 11

Describe how B lymphocytes respond to the influenza virus.

Answer 11

clone (once only);

produce antibodies;

effect of antibody e.g. stimulation of phagocytosis /
precipitation of toxins;

Question 12

New drugs have recently become available for treating influenza. One type is a neuraminidase inhibitor. Explain how this type of drug would act as a treatment for influenza.

Answer 12

alter shape of active site of neuraminidase / block active site;
virus unable to leave host cells;