S1 - Vaccines

Question 1

How do vaccines work?

Answer 1

They mimic natural infection to ‘trick’ the body into building up an immunity to a specific pathogen.

Question 2

What are antigens?

Answer 2

Anything that produces an immune response in the body (Usually the pathogenic components like glycoproteins that act as antigens to our bodies)

Question 3

What are antibodies?

What is another name for antibodies?

Answer 3

Proteins produced by our bodies (By B Cells) that will stick to pathogen antigens.
Immunoglobulins.

Question 4

Which is faster, your first or second immune response to a specific pathogen?

Answer 4

The second.

The first can take anywhere from a few days to two weeks, but the second often takes less than a day.

Question 5

What is a live-attenuated vaccine?

Answer 5

Vaccines that are made with a pathogen that is alive but weakened. The pathogen can still reproduce a little bit, but not cause disease (e.g. the MMR vaccine or the Sabin polio vaccine)

Question 6

What is a killed/inactivated vaccine?

Answer 6

An inactivated or killed vaccine is what it sounds like. The pathogen is completely dead, but the antigen still promotes an immune response (E.g. the Salk polio vaccine or the flu vaccine)

Question 7

What is a toxoid vaccine?

Answer 7

Vaccines made up of an inactivated toxin that the pathogen normally secretes. Mostly used for bacterial infections (E.g. the DTaP vaccine)

Question 8

What is a subunit vaccine?

Answer 8

If only a part of the pathogen is used to make the vaccine, it is referred to as a subunit vaccine (E.g. the Pertussis portion of the DTaP vaccine).

Question 9

What is a gene-based vaccine?

Answer 9

Gene-based vaccines use the injection of a small amount of the pathogen’s genetic material rather than an antigen. The person’s cells uptake the genetic material and produce the antigen themselves, promoting an immune response.

Question 10

What are virus-like particles used as vaccines?

Answer 10

Virus-like particles are a technology where the capsid or envelope of the virus is made in a laboratory but without any genetic material inside. This way, the antigens can be presented to the immune system intact without any risk of the virus causing infection. The HPV vaccine uses this method.

Question 11

What are a few of the main leukocytes involved in immune responses?

Answer 11

T-Cells, B-Cells, and macrophages

Question 12

Describe the two main types of T-Cell.

Answer 12

CD4+ - Helper T-Cells that support the other immune cells

CD8+ - Killer T-Cells that kill our own infected cells

Question 13

Describe the two main types of B-Cell.

Answer 13

Plasma cells - Produce antibodies

Memory B-Cells - Retain immunogenic memory of past antigens the body has seen

Question 14

What do macrophages do?

Answer 14

Ingest foreign materials and enemy cells to present their antigens to T- and B-Cells (They also clean up any debris in the human body).

Question 15

What are vaccine adjuvants?

Answer 15

Adjuvants are chemical additives to vaccines that are able to boost immune response through various mechanisms.

These include possibly clumping vaccine particles at the injection site (which recruits more APCs) or directly stimulating immune cells.

Question 16

What is Thimerosol? Why is it controversial?

Answer 16

Thimerosol is a preservative (not an adjuvant) containing trace amounts of mercury.

It was used in some vaccines to prolong shelf life. It has been taken out of all vaccines given to children under 6, and is only now included in some multi-dose flu vaccine vials.

It is often discussed as one of the possible reasons for the (disproven) hypothesis that vaccines are associated with autism. Some anti-vaccine literature suggests it was used in the MMR shot, however, it never was. Thimerosol was removed as a precaution and other preservatives were used.

Question 17

What is the only type of adjuvant permitted in the U.S.?

Answer 17

Only aluminum-based compounds

Question 18

What is reverse vaccinology?

Answer 18

A method of epitope prediction.

In reverse vaccinology, researchers compare the genetic sequences of many different strains of the pathogen, looking for regions of the genome that are always consistent. These are areas that don’t mutate much, likely because the virus needs that very specific protein for survival. When they identify a region, it becomes a good antigen to potentially include in a vaccine.

Question 19

What is an epitope?

Answer 19

An epitope is the specific chemical site on an antigen to which an antibody binds.

It can be helpful to try to identify good epitopes for antibody binding in advance, instead of having to try many different antigens (This is very difficult for diseases like HIV which mutate very quickly).

Question 20

How are adjuvants different from preservatives?

Answer 20

Adjuvants boost immune responses.

Preservatives prevent contamination (Typically fungal).

Question 21

What is the most common form of vaccine delivery?

What are some other forms?

Answer 21

Intramuscular injection (IM)

Oral vaccines (Usually for live vaccines)
Nasal sprays (Usually for live vaccines)
Vaccine patches

Question 22

Why would vaccine patches be more useful than injections?

Answer 22

You have far more immune cells right under the surface of your skin (to respond to scratches and cuts) than you do deep in your muscles. So delivering vaccine directly under the skin can increase the number of immune cells exposed, and thus the immune response.

It also lowers the risk of accidental needle-sticks for healthcare providers.

Question 23

How does cocooning work in vaccine delivery?

Answer 23

Booster shots are used in some cases to reinforce immunity as immunity can fade over time.

Ex: It is recommended that a DTaP booster be given to all caregivers for newborns and young children.

Question 24

What is the Tdap/DTaP vaccine protective against?

Answer 24

Covers Bordatella Pertussis infection (Whooping cough), diphtheria and tetanus

(Toxoid vaccine)

Question 25

What is the MMRV vaccine protective against?

Answer 25

Measles, Mumps, Rubella (German measles), Varicella (chicken pox)

(Live-attenuated)

Question 26

What is the pneumococcal vaccine protective against?

Answer 26

Pneumococcal disease caused by S. pneumonia

Live-attenuated vaccine

Question 27

What kind of vaccine is the influenza vaccine?

Where is the influenza vaccine mass-produced?

Answer 27

A killed vaccine, unless it’s the nasal spray, which is live-attenuated

The vaccine is incubated in chicken eggs (Although we are shifting over to human cell cultures for incubation)