antibodies and the secondary response + vaccinations + ethical issues

Question 1

what is the structure of Antibodies

Answer 1

Light chain, heavy chain, disulphide bonds, variable region and constant region

• 4 polypeptide chains so have a quaternary structure
• sequence of amino acids in the variable region
  -chains held together by disulphide bonds

Question 2

What does the constant and variable region do

Answer 2

constant - binds to the the phagocyte
variable - complementary and binds to the pathogens

Question 3

why will an antibody only only recognise one antigen

Answer 3

the variable region is complementary to one antigen due to its sequence of amino acids in the primary structure

Question 4

explain the structure of antibodies and explain how this structure relates to their function in the immune response (6)

what features do you put?

Answer 4

• antibodies have a quaternary structure
• variable regions - how they bind to pathogens (complimentary - how)
• constant region - how they bind to phagocytes
• What antibodies do
  . neutralisation
  . agglutination
  . opsonisation

Question 5

What is the secondary response

Answer 5

• memory T/B lymphocytes survive for decades so there is now an increased chance of a foreign antigen encountering the specific receptor
• clonal selection and expansion happen more quickly so more B-cells are activated
• Antibodies are produce faster in greater concentrations so it takes less time to destroy the pathogen and no symptoms will be shown

Question 6

What are the three roles of antibodies

Answer 6

• neutralisation = preventing pathogens from entering the cell
• opsonisation = stimulating the action of phagocytes on the pathogen
• Agglutination = Clumping pathogens together, impairing their functions and increasing the likelihood of phagocytosis

Question 7

What are vaccines

Answer 7

Vaccines induce immune responses to provide protection against the pathogen

Question 8

what are the problems with vaccines

Answer 8

• people can have a poor response (e.g. malnourished and cannot produce antibodies)
• Antigenic variations - variations in the antigens of pathogens causes the vaccines not to trigger on immune response
• Antigenic concealment - when the pathogen ‘hides’ from the immune system by living inside cells

Question 9

what are the different types of vaccines (Definitions)
- live attenuated
- recombinant vector vaccines
- RNA

Answer 9

• live attenuated: modified strain which multiplies slightly but it is not pathogenic
• recombinant vector vaccines: Genes for antigens are transferred to a harmless organism which is injected
• RNA: RNA coding for an antigen is injected in a vesicle. Cells translate the RNA and trigger an immune response

Question 10

What are the different types of vaccines (definitions)
- subunit vaccines
- inactivated
- toxoid

Answer 10

• subunit vaccines: Antigen is extracted and injected. It may be attached to a protein
• inactivated: Killed pathogen is injected. Antigens are intact but there is no multiplication
• Toxoid: toxins are treated with formaldehyde. This triggers the production of antitoxins

Question 11

what is passive and active immunity

Answer 11

Passive - Antibodies aren’t produced by the white blood cells in the body so no memory cells are made

Active - Antibodies are produced by the white blood cells in the body so memory cells are made

Question 12

what is the process the vaccination has in the body

Answer 12

• the Antigen injected binds to a complementary receptor of a B cell
• The B cell is activated then goes through clonial selection and divides via mitosis
• This stimulates cytokines and plasma cells and memory cells form
• the plasma cells then release antibodies

Question 13

What are some ethical issues surrounding vaccines

Answer 13

• usually tested on animals
• Volunteers may be at higher risk of contracting the disease
• Should a vaccine be compulsory for herd immunity
• should the vaccine be free or should people pay for the vaccine
• ## What countries should receive a vaccine first