Manmade Disease Defenses Flashcards
What happens 1-15 days from exposure to pathogen/antigen?
Immune system has created antibodies slowly, but not that many
What happens 30+ days from exposure to pathogen/antigen?
Immune system has destroyed all pathogens and created memory cells
Memory cells are WBCs that remember the pathogen and how to make the correct antibody
What happens on the second exposure to pathogen/antigen?
- quicker and larger production of antibodies
- probably wouldn’t experience any symptoms
What is immunity?
When memory cells can remember a pathogen and make correct antibodies
What are vaccines?
Injecting dead or inactivated pathogens to stimulate an immune response and create memory cells
What is variolation?
The process of using scab tissue from someone previously infected with a pathogen to prevent people from developing the disease
How did Edward Jenner create the first vaccine?
- used cowpox, a similar virus with same antigens as smallpox to create memory cells which could give immunity to smallpox
Why was Jenner’s vaccine unpopular?
- he had unethical methodology
- previous ‘vaacines’ were dangerous
- people didn’t want to be injected with cowpox
What are some issues with vaccines?
- pathogen could mutate, rendering vaccine useless
- not everyone wants to be vaccinated
- possible side effects from immune response such as
• fever and chills
• tiredness
• headache
• muscle and joint aches
• pain, swelling or redness where shot was given
What is herd immunity
Resistance to the spread of an infectious disease within a population that is based on preexisting immunity of a high proportion of individuals as a result of previous infection or vaccination
Benefits and problems of a global vaccination programme?
Benefits
- people are vaccinated
- protects workforce and economy
- provides jobs
- can completely wipe out pathogen
Problems
- global agreement is hard to achieve
- expensive
- slow
- inequality
Define drug
Any chemical that alters how your body works
What are medicines and how do they treat disease?
- useful drugs
- relieve symptoms or treat/care underlying illness, often by destroying pathogen
How do antibiotics prevent bacterial disease?
- by interfering with pathogens metabolism, e.g prevent development of cell wall or block action or ribosomes
OR
- by slowing bacterial growth long enough for immune system to get on top of them
What can antibiotics only damage
BACTERIAL PATHOGENS
What are some issues with antibiotics?
- don’t work against other pathogens
- specific to specific bacteria
- can harm good bacteria too
How were antibiotics discovered and by who?
- Alexander Fleming
- was investigating cures for Staphylococcus
- went on holiday without fully cleaning lab
- came back to find mould had contaminated petri dishes, and no bacteria was growing around the mould.
- He concluded the mould must have a chemical that destroys the bacteria,
- turns out it was a penicillin fungi, so he called the antibiotic ‘penicillin’
How does antibiotic resistance come about?
- bacteria divides by binary fission
- random mutation produces antibiotic resistant bacteria
- person takes antibiotics, and all die except resistant bacteria
- bacteria divides and produces new group of antibiotics resistant bacteria
How to reduce risk of development of antibiotic resistant bacteria?
- doctors should not prescribe antibiotics inappropriately, only for bacteria
- patients must complete their course of antibiotics so all bacteria are killed, and none survive to mutate and form resistant strains
- agricultural use of antibiotics should be restricted
Where is the heart drug digitalis from?
Foxgloves
Where is penicillin from?
Penicillum mould
Where is aspirin from?
Willow bark
Where are opiates from?
Poppy seeds
How do antiviral drugs treat viral infections?
They only slow down viral development
Why is or difficult to make an antiviral drug?
They often damage body cells
What must all drugs be before they can be prescribed and taken?
- effective
- have a clear dosage
- safe
- stable (stay good over a long period of time)
What are the 2 main parts of preclinical testing?
- laboratory testing
- animal testing
What occurs in labatory testing
- computer modelling and human skin cells from stem cells
- tests for effectiveness and side effects
What occurs in animal testing?
- tests done on many animals, but mainly ones that show some relatedness to humans
- continues to test for effectiveness and side effects
What occurs in the first stage of clinical testing (phase 1)
- drug is tested on healthy volunteers to ensure safety
(10-100 volunteers)
What occurs in the second stage of clinical testing (phase 2)
- Ill volunteers are given drug, to test for effectiveness
- dose is developed here, starting with low dose and increasing until optimum safe dose found
(200-400 volunteers)
What occurs in the third stage of clinical testing (phase 3)
- a double blind trial occurs, using placebos
- peer review takes place
- 3000+ volunteers
What are monoclonal antibodies?
Many copies of the same antibody produced in a lab
Why do we need MABs?
Lymphocytes can’t divide after they start producing proteins
What are fused lymphocyte-tumor cells called?
Hydridomias
What is the process of making MABs?
- mouse injected with specific antigen, stimulating lymphocytes to produce specific antibody
- lymphocytes extracted and combined with a particular kind of tumor cell using detergents to break down cell membranes allowing them to fuse,
- a hybridomia is formed which can divide and produce antibodies
- hybridomias are screened to check for antibody production, single hybridomia cells cloned to produce many cells that produce same antibody. These are MABs
- large amount of MABs collected and purified
Uses of MABs?
- diagnosis eg. Pregnancy test
- in labs to measure hormone and chemical levels, to detect pathogens
- in research to locate/identify specific molecule in cell/tissue by binding to them with fluorescent dye
- to treat some disease eg. cancer by binding to cancer treatment drugs, delivers it to cancer cells without harming other body cells
What is peer review?
Other scientists in your field reviewing your work for validity and ethics
How do pregnancy tests work?
They rely on MABs which bind to hormone HCG which is found in the urine of a woman in the early stages of pregnancy
Reaction zone contains MABs specific to HCG with an an Enzyme attached that can activate dye molecules
Describe the state of a pregnancy test before use
- reaction zone (where urine is placed) contains MABs specific to HCG
- results zone contains immobilised (will stay in its zone and not move up with urine) MABs specific to HCG
- control zone contains immobilised antibodies complementary to antibodies from results zone
Hey so plsplspls look at your book for the rest of pregnancy tests its really hard to do on here
What is an antiseptic?
A chemical that kills microbes outside the body
What is an independent variable?
The variable you change
What is a dependant variable?
The variable you measure
What is a control variable?
The variable you keep the same
What is the zone of inhibition?
The area where no bacteria grows on an agar dish
