Ch. 18 Practical Applications of Immunology: Vaccines

Question 1

vaccine

Answer 1

suspension of organisms or fractions of organisms used to induce immunity.

Question 2

Variolization

Answer 2

form of “vaccination” for smallpox in 1400s China/Turkey

• Scarring, high death rate, want to avoid
• They would take something sharp, puncture the pustule, and poke it under the skin of healthy individuals (“immunising” against smallpox)
• Lady Mary Wortley Mantagu (1700s) wrote epistolary essays; had her own children variolized, introducing the practice to England and popularising it

Question 3

Edward Jenner (1798)

Answer 3

• noted that milkmaids who got cowpox seemed to be protected from smallpox
• injected cowpox into a boy, six weeks later infected him with smallpox and he did not get it
• thus, “vaccination” was born

Question 4

three principles of vaccination

Answer 4

1) provokes primary immune response without the disease, circulating antibodies and triggering memory cells.
2) secondary response upon exposure to pathogen
3) herd immunity (when most of the population is vaccinated)

Question 5

issues in vaccine developments

Answer 5

• finding the most effective antigens
• which branch of the immune system is activated?
• life cycle of the pathogen
• testing of efficacy
• $ (return on investment)

Question 6

Types of vaccines (3)

Answer 6

• live attenuated (weakened pathogen)
• killed/inactivated
• subunit vaccines (antigenic fragments)

Question 7

Live attenuated vaccine advantages and disadvantages

Answer 7

Adv:
- closely mimics natural infection
- replicates within host
- may confer lifelong immunity
- fewer boosters
Disadv:
- may revert to virulent form
- storage

Question 8

Killed/inactivated vaccine advantages and disadvantages

Answer 8

Adv:
- safer than attenuated
- storage
Disadv:
- need repeated boosters
- induce primarily humoral immunity

Question 9

Subunit vaccine subtypes

Answer 9

• recombinant (DNA vaccines)
• toxoid
• virus-like particle (VLP; empty virion with no genetic material)
• polysaccharide (weak antigens)
• conjugated

Question 10

recombinant (DNA) vaccines mechanism

Answer 10

• isolate genetic material from pathogen
• insert into altered plasmid
• insert plasmids via syringe or gene gun; enters cell nucleus
• human cells make bit of protein antigenic from vaccine, express/secrete it
• immune system makes antibodies, T cells

Question 11

recombinant vector

Answer 11

nonvirulent bacteria or viruses genetically modified to deliver genes coding for antigen

Question 12

COVID is a _____

Answer 12

RNA virus (not retrovirus).
Has various surface proteins, but the strongest response is from the Spike (S) glycoprotein.

Question 13

mRNA COVID vaccines

Answer 13

Pfizer and Moderna

• RNA codes for S protein
• enters your cells, your ribosomes process mRNA –> S protein
• S protein expressed on surface of your own cells
• antibody-producing and T cells respond

Question 14

DNA/viral vector COVID vaccine

Answer 14

Johnson & Johnson

• vector carries bit of DNA into the nucleus
• produces S protein
• has caused blood clotting in some people

Question 15

Adjuvant

Answer 15

chemicals added to improve effectiveness (appropriate secondary response)

approved for human use: Alum, modified lipid A

Question 16

Potential future of vaccines

Answer 16

• plants as host to develop vaccines (no animal host)
• oral vaccines (less trained personnel, compliance)
• dry vaccines (skin has high APCs; no refrigeration)
• multiple-combination vaccines
• vaccines for chronic diseases
• vaccines for t-cell immunity

Question 17

safety

Answer 17

• may cause disease on rare occasions (esp attenuated)
• NO evidence MMR vaccine causes autism
• still the safest and most effective way of preventing infectious disease in children