immunity, vaccinations, antibiotics and other medicines

two types of immunity

active

passive

active immunity

• your immune system makes its own antibodies after being stimulated by an antigen

two types of active immunity

• natural - immune after catching a disease

• artificial - immune after given a vaccination

passive immunity

immunity from being given antibodies made by a different organism without your immune system producing any of its own

two types of passive immunity

• natural - baby becoming immune due to mothers antibodies from the placenta and breast milk

• artificial - immunity from injection of antibodies made by another individual such as snake antivenom

passive immunity features to compare

• no exposure to antigen

• protection is immediate

• protection is short term

• memory cells arent produced

active immunity features to compare

• requires exposure to antigen

• takes a while for protection to develop

• protection is long term

• memory cells are produced

autoimmune disease

• a disease which results from the immune system accidentally triggering the immune response in your body instead of protecting it and causes own healthy cells to be damaged

• usually chronic

autoimmune disease examples

• lupus

• rheumatoid arthritis

• crohns disease

lupus

• damage to connective tissue and painful inflammation

• can affect the skin, joints, heart, lungs and kidneys

• sometimes causes a butterfly rash on the face

rheumatoid arthiritis

• causes pain and inflammation in the joints

• can lead to muscle spasms

crohns disease

• inflammation of the gut

• diarrhea, stomach aches and cramps

what is a vaccine

a way of stimulating an immune response so that immunity is achieved

how do vaccines work

• contain a harmless or weakened version of the pathogen

• or a toxoid (harmless version of a toxin)

• so an immune response is stimulated and memory cells are produced

what does an effective vaccination programme include

• enough supply of the vaccine

• updating the vaccine

• good storage conditions of the vaccine

• few side effects

what could happen that would cause a vaccine to be innafective

• antigenic variation

• antigenic shift

• antigenic drift

• antigenic concealment

antigenic variation

• pathogens mutate along with their antigens

• so vaccine antibodies may become obselete

antigenic shift

• where there are major changes in the same strain of virus antigen

antigenic drift

• changes over time to the antigens

antigenic concealment

where the pathogen hides from the vaccine by

• living in host cells

• parasiting immune cells

• remaining in difficult to reach parts of the body

herd immunity

• when a large proportion of the population are vaccinated against the disease

• the risk of a susceptible person coming into contact with an infected person is extremely low

• even people who havent been vaccinated are unlikely to catch it because theres no one to catch it from

• prevents epidemics

ethical concerns with vaccines

• who to trial the vaccine of

• animal welfare concerns

• development expensive and may take money from other treatments

antibiotics

• chemicals that kill or inhibit the growth of bacteria inside the body

why are antibiotics so useful

they target bacterial cells without damaging human body cells

how do antibiotics work

• destroy cell wall

• inhibit DNA/RNA production

• inhibit reproduction

• disrupting protein synthesis

who discovered penicillin

Alexander Flemming in 1928

how does antibiotic resistance spread

• antibiotic resistant strain survives and reproduces

• allele for antibiotic resistance passed on to offspring

• natural selection

how do strains of bacteria become antibiotic resistant

genetic variation in a population through mutation

what factors can cause antibiotic resistance

• over use and improper prescription

• extensive use in agriculture

• people not finishing their course of antibiotics

bacteria resistance through natural selection process

1. bacteria mutates randomly giving them resistance to antibiotics

2. antibiotics will kill all the non resistant bacteria leaving the resistant ones

3. resistant ones will reproduce by binary fission and spread the allele for resistance through the population

4. increasing its allele frequency

MRSA

antibiotic resistant bacteria that causes serious wound infections

Clostridium difficile

antibiotic resistant bacteria that infects the digestive system and produces a toxin that causes severe diarrhoea, fever and cramps

pros of using antibiotics in agriculture

• can lead to more animals being kept in close proximity to increase yield, keep profits and supply for farmers

cons of using antibiotics in agriculture

• driver for antibiotic resistance because they are used in animals even when theyre not sick

• can lead to less diversity in the environment microbiome

digoxin

from foxgloves and used to treat fibrilation and heart failure

vanomycin

from soil fungi and is one of the most powerful antibiotics

aspirin

from willow tree bark and in a painkiller and anti inflammatory

paclitaxel

from yew bark and used to treat breast cancer

penicillin

from penicillium fungus and was the first antibiotic

piralt

from cone snails venom and is a painkiller 1000x stronger than morphine

why do possible sources of medicine meed to be protected

• preserving habitats can allow the discovery and extraction of more compounds for medicine

• so species dont die out before we get a chance to study them

personalised medicine

medicine tailored to the DNA of an individual so doctors know what drugs are are the most effective for you

what are scientists hoping for personalised medicine

• that by studying the relationship between someones genetic makeup and their responsiveness to drugs, more effective drugs can be produced in the future

sythetic biology

involves using technology to design and make things like artificial proteins, cells and microorganisms

how are scientists looking at using synthetic biology

engineering bacteria to destroy cancer cells while leaving healthy body cells intact