15 - Vaccines; History and Passive Immunisation - Watson

Question 1

Why are vaccines one of the most effective “weapons” in the medicinal armoury?

Answer 1

cost effective -> economic
successful
when relating to pharmaceuticals eg anti-cancer drugs with lengthy clinical trials, expensive drug discovery etc

Question 2

Name some diseases that have been either eradicated or hugely reduced as a result of vaccines

Answer 2

• Diptheira
• Tetanus
• poliomyelitis
• smallpox (last NATRUAL case = 1977)

Question 3

Give an example of a disease stating its pre-annual morbidity and its morbidity post vaccine introduction

Answer 3

Diptheria; around 21,000 per annum now reduced to 0

Question 4

What diseases are iron lungs for and what are the downsides of using them?

Answer 4

poliomyelitis - causing paralysis of the diaphragm so can no longer breath

• hugely life-limiting
• cannot move / lead normal life

Question 5

Name 2 diseases to date in which vaccines are highly needed

Answer 5

ebola and HIV/AIDS

Question 6

How many new infections of HIV do we see per day and briefly describe its effects in terms of economies etc

Answer 6

16,000 new infections per day 
pandemic 
no effective vaccine 
detrimental impacts on economies 
destroys household income and human capital because antiretroviral drugs do exist that can control the symptoms/treatment NOT cure however these are v expensive

Question 7

Describe Ebola

• how contagious
• death rate
• vaccine?
• anything else

Answer 7

highly contagious
20-90% death rate
new strains emerge at any time
Merck have just had Ebola Zaire Virus vaccine approved for use by the FDA in Dec. effective against Zaire Ebolavirus
normally self-limiting because makes people too sick to travel therefore cannot pass on disease

Question 8

What is variolation?

Answer 8

eg scratches on arm inoculated with pus from pustule as a form of developing immunity
infection with a mild case protects the individual from severe infection later

Question 9

What were the origins of vaccination?

Answer 9

Edward Jenner noticed that milkmaids (consistently infected with cowpox) were resistant to infection by small pox
cowpox = less virulent version of smallpox
innoculated an 8yo boy with pus from cowpox pustule -> immunity

Question 10

Name the 2 men and state their contributions to the development of the immunological theory.
also state what immunological theory is

Answer 10

immunological theory;
1) diseases are caused by microorganisms
2) protective action of a previous disease
Robert Koch - Koch’s postulates. related a specific disease to a specific variety of micro-organism
Louis Pasteur - developed a rabies vaccination. used weakened pathogen to artificially infect a patient. became immune to disease (still used to this day)

Question 11

BRIEFLY describe passive immunisation

Answer 11

transfer of preformed Abs to the circulation

does not involve activation of IS

Question 12

Give the 2 types of passive immunisation

Answer 12

natural or artificial

Question 13

What is natural passive immunity? give an example and state which diseases it is protective against

Answer 13

eg transfer of natural maternal Abs across the placenta to the unborn, developing foetus
IgG
diseases; polio, mumps, rubella, diphtheria, tetanus

Question 14

Give 3 examples of when we need to use artificial passive immunity

Answer 14

1) B cell defects therefore cannot produce own Abs (inherited or acquired) - individuals with agammaglobulinaemias. injected with pooled human IgG
2) exposure to disease (eg measles) could cause complications. those with weakened immune systems eg those on chemotherapy can’t be injected w/ attenuated forms of disease
3) no time for active immunisation to give immunity. eg pathogen with v short incubation period

Question 15

Prior to vaccines/antibiotics ____ ____ was the major treatment for a range of ____ ____

Answer 15

passive immunisation

infectious diseases

Question 16

How were Abs generated that neutralised toxins? What are some problems with this?

Answer 16

using horse antisera.
serum sickness - immune response to horse serum.
if for eg have exposure to another toxin cannot inject horse serum again because will get an immune response to the serum

Question 17

Why is it said that in some cases the concern isnt to do with the primary infection itself?

Answer 17

because the immune system can develop against this infection in time. however the toxins produced are v potent and the IS does not have Time to develop against these

Question 18

Give an example of 2 very common toxins and the organisms that produce them

Answer 18

tetanus; Clostridium tetani

botulinum; Clostridium botulinum

Question 19

Why is natural immunity to the botulinum toxin hard to achieve?

Answer 19

lethal dose of botulinum toxin = 1.5ng/kg intravenous

exposure to sufficient amounts of toxin to stimulate IS therefore lethal

Question 20

State how we do get some immunity to certain toxins

Answer 20

eg tetanus toxoid

certain toxins can be weakened/deactivated in order to generate an IR (active immunisation)

Question 21

Give the 3 main types of passive immunisation, what they are effective against and give examples of each

Answer 21

ANTI-TOXINS; Diptheria, tetanus, botulinum
USED PROPHYLACTICALLY AFTER EXPOSURE TO LIMIT CHANCES OF INFECTION; hepatitis, rabies, measles
ANTI-VENINS; snake bite, insect bite, jellyfish

Question 22

Give 3 advantages of passive immunisation

Answer 22

1) when immune responses too SLOW, can use pre-formed Abs to neutralise toxins / venoms
2) w/ highly virulent pathogens, pre-formed Abs can be used to limit/prevent infection
3) in case when vaccines dont exist, pre-formed Abs given that have been generated in immunised animals / engineered eg Ebola. in some cases Abs from surviving patients may be used

Question 23

Give 3 downsides of passive immunisation

Answer 23

• no immunological memory
• no long term protection
• possible reaction to antisera (cross species)

Question 24

Describe active immunisation

Answer 24

• manipulating the immune system to generate a persistent, protective response against pathogens
• immunisation with a vaccine that triggers an immune response and safely mimics a natural infection (or toxoid)
• trigger both arms of the immune response and generate immunological memory

Question 25

What are the aims of a perfect vaccine and what do vaccines depend on?

Answer 25

• generate immunological memory - memory B/T cells
• stimulate B/T cell responses
• generate long term protection ideally from a small no. immunisation

depends on the nature of the pathogen (incubation time, toxins?) and natural history of disease

Question 26

The importance of memory ) _ ____ response depends on the nature of the pathogen

Answer 26

B cell

Question 27

Draw a graph highlighting 1ry/2ndry responses of [Ab] in serum against time
annotate this graph

Answer 27

311 - 15 word

Question 28

give an example of a disease with a rapid onset, what this means for the body and how we can overcome this

Answer 28

influenza - rapid onset

• onset is too quick for immunological memory to be activated
• infection of tissues can be blocked by Ab therefore need high levels of neutralising Ab consistently circulating
• this is why we have repeated booster injections to keep this level of Ab high
• as well “escape” variants require new generation of vaccines
• contrasted with Polio. 3 days for infection to be established in the nervous system. gives us time for immunological memory to be activated and neutralising Abs produced

Question 29

Is it enough to activate B cells just from their Ab binding to antigen?

Answer 29

Abs bound to B cell surfaces do recognise antigens and sometimes this is enough for B cell activation and Ab production. however other occasions, T cells required too for this to happen

Question 30

BRIEFLY describe the stages of active immunisation

Answer 30

1; INNATE IMMUNE SYSTEM
- immunisation needs to elicit danger signals (PAMPs) to activate INNATE system
- TLRs activated. produce pro inflammatory cytokines
- specialised APCs activated eg DCs
2; ADAPTIVE
- these link to adaptive system to generate B/T cells (and memory cells) as well as producing Abs and T cell responses