Antibodies can protect the body from pathogens in several ways.
Which of the options below will not occur following antigen-antibody binding?
Increased susceptibility to phagocytosis.
Neutralisation of toxins to make them harmless.
Secretion of histamine to produce an allergic reaction.
Agglutination of bacteria to reduce their spread.
A child is given a vaccine for a viral disease. A few months later she is in contact with the same virus.
What is the expected response to the second contact with the virus?
Increased number of T-lymphocytes.
Large numbers of antibodies are released.
Large numbers of antigens are released.
Increased number of B-lymphocytes.
When a B-lymphocyte is activated by an antigen, what action is taken?
It engulfs the infected body cell which displays a complementary antigen.
It secretes signalling proteins that stimulate T-lymphocytes to produce plasma cells.
It divides repeatedly to form clones of genetically identical plasma cells.
It attaches to the infected cell displaying the antigen and destroys it.
Which type of molecule is most important to directly identify a cell as non-self?
Proteins
Phospholipids
Carbohydrates
Nucleic acids
The amount of antibody produced in response to an antigen in a vaccine is shown in the graph below.
Which statement about the graph is correct?
The second exposure to the antigen occurred at 25 days.
T-helper lymphocytes are activated on day 12.
Memory cells for this antigen are present in the body within 20 days.
The secondary immune response begins at around day 35.
