12.7 Preventing & Treating Disease Flashcards
What are the 2 types of adaptive immunity
naturally acquired and artificially acquired
What are the 2 types of naturally acquired immunity
active and passive
What’s naturally acquired ACTIVE immunity
antigens enter the body naturally; body induces antibodies and specialised lymphocytes
What’s naturally acquired PASSIVE immunity
antibodies pass from mother to foetus via placenta or through breastmilk
What is natural immunity in babies (PASSIVE)
Some antibodies are passed through the placenta but most are passed in the colostrum (first milk a mammalian mother makes). It’s extremely high in antibodies and strengthens the baby’s immune system to be as good as the mother’s.
Antibodies are absorbed into bloodstream in the gut.
What are the 2 types of artificial immunity
active and passive
What’s PASSIVE artificial immunity
For some fatal diseases, antibodies can be made by one individual, extracted and inserted in the blood of someone else.
Doesn’t last long but can be life saving.
Examples are tetanus, rabies. Could work for COVID.
What’s ACTIVE artificial immunity
When the immune system is stimulated to make its own antibodies to a safe form of the antigen. The antigen is not normally from a ‘live’ pathogen as this could be harmful.
Called a VACCINATION
What are the differences between active and passive immunity
- active requires exposure to antigens, passive doesn’t
- active takes a while for protection to develop, passive is immediate protection.
- active is long-term, passive is short term protection.
- memory cells ARE produced in active, not in passive
What is a vaccination
vaccine stimulate the production of antibodies and memory cells against the target pathogen without causing illness
Why don’t vaccines cause illness
- they may contain inactivated forms of the pathogen (killed by heat treatment so only useful antigens are intact) e.g. Whooping cough
- toxin molecules that have been altered and detoxified. e.g. tetanus
- may contain less virulent form of pathogen (Rubella & polio)
- may contain isolated antigens from pathogen; e.g. flu
- GM antigens; e.g. Hepititis B
How does a vaccination work
- pathogens are made safe
- small amounts of the safe antigen are injected in blood (this is the vaccine)
- primary immune response is triggered so antibodies and memory cells are produced
- secondary response is triggered if pathogen reoccurs.
What are the disadvantages of vaccines
can take years to produce; with the flu vaccine, scientists have to predict which strain of flu is most likely to be around in next year and produce vaccine for that one; expensive.
What are the advantages of vaccines
vaccines give long term immunity to a specific pathogen;
can be used in epidemics and pandemics;
mass vaccinations can be produced;
herd immunity can occur - if a big no. of people are vaccinated, those who aren’t are still protected as a result.
What are examples of diseases yet to be treated successfully by a vaccine
HIV and maleria
What are medicines
some treat communicable diseases, some non-communicable, some relieve symptoms, some attack the pathogens
What are examples of medicines that treat the illness
chemotherapy drugs, antibiotics, antifungals
What are sources of medicines
most come from fungi, moulds or plants.
Alexander Flemming is noted with discovering first safe antibiotic (penicillin)
Why do forests and other areas of land need to be protected
because they could be potential sources of medicine.
Many medicines use natural compounds found in rainforests, animals, plants, microbes etc.
Some cancer drugs are made using soil bacteria and daffodils are grown to help with treatments for Alzheimer’s.
What are examples of widespread medicines
Penecillin - originally sourced from mould growing on melons - an antibiotic against bacertia
Aspirin - sourced from compounds in willow bark - a painkiller and anti-inflammatory
Digoxin - originally extracted from foxgloves - a powerful heart drug used to treat atrial fibrillation and heart failure
What are pharmacogenetics
personalised medicine methods- combination of using drugs with an individuals genome and disease information
how is pharmacogenetics possible now
because analysing a person’s genome is relatively easy and cheap to do now
What’s an example of pharmacogenetics
in approx. all breast cancers, there is a mutation called the HER2 gene; Herceptin and lapatinib shut down the gene activity. Doctors can reduce death from HER2 by 50% by analysing breast tumours and drugs.
What is synthetic biology
Using techniques of genetic engineering, we can develop popn.s of bacteria to produce needed drugs that are usually too rare, expensive
What’s the antibiotic dilemma
Antibiotics are becoming resistant very quickly which is concerning because they’re very new to treatments. The dilemma is knowing when to prescribe them and when to know they’re not needed.
What is selective toxicity
Antibiotics interfere with the metabolism of the bacteria without affecting the metabolism of the human cells.
What has caused antibiotics to become resistant
A random mutation may have occurred during bacterial reproduction. This would cause the whole species to be resistant; this would be an advantageous characteristic which would be passed on to daughter cells.
What are examples of highly resistant bacteria
methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile
MRSA: bacterium carried on nose/skin of 30 % of popn.;
causes boils, abscesses and septicaemia
C. difficile: bacterium in the gut of 5% of pop.; produces toxins that damage intestines, bleeding, diarrhoea
How can antibiotic resistant infections be reduced in the long term
- minimising use of antibiotics and ensuring people who do need them use them for the whole course to prevent it coming back as a resistant strain
- good hygiene in hospitals, care homes to stop spread
