15 - Vaccines; History and Passive Immunisation - Watson Flashcards
Why are vaccines one of the most effective “weapons” in the medicinal armoury?
cost effective -> economic
successful
when relating to pharmaceuticals eg anti-cancer drugs with lengthy clinical trials, expensive drug discovery etc
Name some diseases that have been either eradicated or hugely reduced as a result of vaccines
- Diptheira
- Tetanus
- poliomyelitis
- smallpox (last NATRUAL case = 1977)
Give an example of a disease stating its pre-annual morbidity and its morbidity post vaccine introduction
Diptheria; around 21,000 per annum now reduced to 0
What diseases are iron lungs for and what are the downsides of using them?
poliomyelitis - causing paralysis of the diaphragm so can no longer breath
- hugely life-limiting
- cannot move / lead normal life
Name 2 diseases to date in which vaccines are highly needed
ebola and HIV/AIDS
How many new infections of HIV do we see per day and briefly describe its effects in terms of economies etc
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
Describe Ebola
- how contagious
- death rate
- vaccine?
- anything else
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
What is variolation?
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
What were the origins of vaccination?
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
Name the 2 men and state their contributions to the development of the immunological theory.
also state what immunological theory is
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)
BRIEFLY describe passive immunisation
transfer of preformed Abs to the circulation
does not involve activation of IS
Give the 2 types of passive immunisation
natural or artificial
What is natural passive immunity? give an example and state which diseases it is protective against
eg transfer of natural maternal Abs across the placenta to the unborn, developing foetus
IgG
diseases; polio, mumps, rubella, diphtheria, tetanus
Give 3 examples of when we need to use artificial passive immunity
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
Prior to vaccines/antibiotics ____ ____ was the major treatment for a range of ____ ____
passive immunisation
infectious diseases
How were Abs generated that neutralised toxins? What are some problems with this?
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
Why is it said that in some cases the concern isnt to do with the primary infection itself?
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
Give an example of 2 very common toxins and the organisms that produce them
tetanus; Clostridium tetani
botulinum; Clostridium botulinum
Why is natural immunity to the botulinum toxin hard to achieve?
lethal dose of botulinum toxin = 1.5ng/kg intravenous
exposure to sufficient amounts of toxin to stimulate IS therefore lethal
State how we do get some immunity to certain toxins
eg tetanus toxoid
certain toxins can be weakened/deactivated in order to generate an IR (active immunisation)
Give the 3 main types of passive immunisation, what they are effective against and give examples of each
ANTI-TOXINS; Diptheria, tetanus, botulinum
USED PROPHYLACTICALLY AFTER EXPOSURE TO LIMIT CHANCES OF INFECTION; hepatitis, rabies, measles
ANTI-VENINS; snake bite, insect bite, jellyfish
Give 3 advantages of passive immunisation
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
Give 3 downsides of passive immunisation
- no immunological memory
- no long term protection
- possible reaction to antisera (cross species)
Describe active immunisation
- 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
What are the aims of a perfect vaccine and what do vaccines depend on?
- 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
The importance of memory ) _ ____ response depends on the nature of the pathogen
B cell
Draw a graph highlighting 1ry/2ndry responses of [Ab] in serum against time
annotate this graph
311 - 15 word
give an example of a disease with a rapid onset, what this means for the body and how we can overcome this
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
Is it enough to activate B cells just from their Ab binding to antigen?
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
BRIEFLY describe the stages of active immunisation
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
