14. Vaccination

Question 1

What is the primary aim of vaccination?

Answer 1

Stimulate production of memory T and B cells, without causing significant pathology

Question 2

What types of antigens are used for vaccinations?

Answer 2

1. Attenuated - alive but not able to cause substantial disease (not good to give to immunodeficient people)
2. Dead organisms - not as good at stimulating immune response
3. Subunits - protein/polysaccharides mixed with adjuvants
4. Inactivated toxin - toxoid

Question 3

What are adjuvants and carriers?

Answer 3

Adjuvant - something that nonspecifically stimulated specific immune response

Carrier - if using bits of organisms, then link them to much bigger protein which is taken up by dendritic cells and processed and presented to T cells (e.g. polysaccharides)

Question 4

What are the adverse effects of vaccination?

Answer 4

Immunocompromised host, side-effects (especially neurological)

Question 5

What is the difference between the primary and secondary immune response?

Answer 5

Primary immune response is weak and short lived, creation of memory cells (this is what you want to stimulate with vaccinations), secondary is more severe and lasts longer

Question 6

What are the requirements for a successful vaccine?

Answer 6

Effective - right type of immune response
Available -
Stable - no everywhere has access to refrigeration
Inexpensive
Safe

Question 7

What are the components of a vaccine?

Answer 7

Antigen (whole organism), carrier, adjuvant

Question 8

Who developed the initial smallpox vaccine (first successful vaccine)?

Answer 8

Edward Jenner in 1798

Question 9

When was Rinderpest and smallpox eliminated?

Answer 9

1979 - Smallpox

2011 - Rinderpest

Question 10

What response does the live attenuated polio vaccine achieve?

Answer 10

Causes a very good IgA response in the area that the polio enters the body (if you used killed polio then doesn’t give the right response)

Question 11

Which countries is polio still prevalent?

Answer 11

Afghanistan, some places in central Africa

Question 12

What is the influenza problem?

Answer 12

Flu vaccines work well most of the time, but flu can change - point mutations (antigenic drift - antigens partly changed), exchange (antigenic shift - whole genomes switched - much more severe, antigens completely altered)

Question 13

What are the two main antigens of influenza?

Answer 13

Hemoagglutinin, neuraminidase

Question 14

How are flu vaccines produced?

Answer 14

In fertilised chicken eggs

Question 15

How often does the flu vaccine production occur?

Answer 15

Twice a year, once for each flu season in the northern and southern hemisphere

Question 16

What are the problems in developing an effective HIV vaccine?

Answer 16

Identification of immunogens (antigens which generate correct antibodies) and immunisation strategy which induce broad and long-lasting cytotoxic T cell immunity and broadly neutralising antibodies

Question 17

What is an immunogen?

Answer 17

Antigen which generate correct antibodies

Question 18

What has been the only slightly successful HIV vaccine?

Answer 18

4 priming injections of canarypox vector vaccine with HIV gag, pol & env genes, and 2 booster injections - shows limited effect (~30%)

Question 19

What are conjugate vaccines? What diseases?

Answer 19

Carbohydrate vaccines - created by coupling a carbohydrate onto a protein (protein needed for activation of T cells) e.g. Haemophilia influenza type B (causes meningitis & pneumonia), Meningococcus group C

Question 20

What are the vaccines/timings given to at risk groups?

Answer 20

BCG vaccine - 0-35years
Chickenpox vaccine - any 
Flu vaccine - children & adults
Pneumococcal vaccine - 2-65years
Hepatitis B vaccine - birth onwards

Question 21

What are the main travel vaccines?

Answer 21

Diphtheria, polio, tetanus, typhoid, Hep A, Hep B, cholera, japanese encephalitis, tick-borne encephalitis, meningococcal meningitis, rabies, tuberculosis, yellow fever

Question 22

What is the ‘best’ vaccine?

Answer 22

no side effects, one shot protection for life

Question 23

What is really great about the yellow fever vaccine?

Answer 23

Gives lifelong immunity

Question 24

What is a gene gun? What are the benefits?

Answer 24

A method of vaccination which injects genes which encode proteins or the proteins themselves. Causes much greater cytotoxic T cell activation than regular vaccination - very effective in animals but not great in humans

Question 25

What is the future of vaccination?

Answer 25

Polio eradication, effective HIV, TB, malaria vaccines, broad flu vaccine, therapeutic vaccines, DNA vaccines, vaccines against parasites