types of immunity Flashcards
define active immunity
exposure to antigen, triggering specific immune response, antibodies made by individual
define passive immunity
no exposure to antigen, pre-made antibodies received by individual
define artificial passive immunity
results from administration of antibodies from another animal against a dangerous pathogen
define artificial active immunity
results from exposure to a safe form of a pathogen like in vaccination
define natural active immunity
results from response of body to invasion of a pathogen
define natural passive immunity
given to an infant mammal by the mother through the placenta/breast milk
define autoimmune disease
condition/illness resulting from the immune system acting against its own cells and destroying healthy tissue in the body
name 3 examples of autoimmune diseases
- Type 1 diabetes
- Rheumatoid Arthritis
- Lupus
suggest how autoimmune diseases may occur
occur when the immune system recognises ‘self’ antigens as ‘non self’, triggering immune response against its own cells
define vaccine
safe form of an antigen injected into bloodstream to provide artificial active immunity against a pathogen bearing the antigen
describe 5 ways in which antigens can be obtained for use in vaccines
- killed/inactivated bacteria and viruses
- weakened strains of live bacteria/viruses
- toxin molecules that have been altered/detoxified
- isolated antigens extracted from the pathogen
- genetically engineered antigens
describe how vaccination results in artificial active immunity
- small amount of safe antigen-containing vaccine is injected into blood
- primary immune response triggered by foreign antigens and body produces antiodies + memory cells as if infected by live pathogen
- if in contact with that pathogen, but live, secondary immune response triggered and pathogen destroyed rapidly before suffering symptoms of disease
define epidemic
when a communicable disease spreads rapidly to a lot of people at a local/national level
define pandemic
same disease spreads rapidly across a number of countries and continents
define herd immunity
large part of population of an area is immune to a disease making the chances of an outbreak very low
explain how vaccination of a significant number of people in a population can provide protection for unvaccinated people
If enough people vaccinated, herd immunity is reached = less transmission and less likely for disease to reach an unvaccinated person - it cannot spread through a population that is already immune
suggest which members of a population are likely to need protection through herd immunity.
- people allergic to vaccine
- people with weakened immune systems that need to take immunosuppressants
suggest why the influenza vaccine needs to be redeveloped and people need to be revaccinated each year.
- virus causing flu mutates regularly so antigens on surface change too
- vaccines must be redeveloped as people will no longer be able to form secondary response against the mutated variant
explain the need to maintain biodiversity in relation to discovery of new medicines.
ensure we do not destroy an organism which could be key to a life-saving drug
define personalised medicine
combination of drugs that work with your individual combination of genes and disease
give an example of how treatment is being personalised
30% of breast cancer patients have mutation on a certain gene
- activity of that gene can be shut down by a drug
suggest the value of personalising medicine to a persons genetic information
improve how diseases are treated by working out the best approach for a specific person
define synthetic biology
design and construction of new biological parts, devices and systems and re-designing existing natural biological systems for useful purposes
give 3 examples of how synthetic biology may lead to better medical treatments
- develop bacteria using genetic engineering that can produce drugs that are rare/expensive
- genetically modify mammals to produce therapeutic proteins in milk
- nanotechnology to deliver drugs to specific sites in cells
define antibiotic
chemical that kills or inhibits bacterial growth
define selective toxicity
ability to interfere with the metabolism of a pathogen without affecting the cells of the host
suggest ways in which antibiotics may act selectively on bacterial cells but not human cells.
- destroy/affect peptidoglycan production - humans dont need it + it is what the bacterial cell wall is made of
- target their metabolic pathways and not human ones
explain why antibiotics do not work on viral infections
- specifically target bacterial machinery
- viral infections have completely different structure and are non-living
- viral infections do not have cell wall that can be attacked - protein coat instead
outline different ways 4 common antibiotics have their effect
- penlillin and cephalosporins weaken cell wall so bacterium more easily damaged by immune reaction
- sulfonamides interfere with metabolic reactions
- tetracyclines and streptomycin inhibit protein synthesis
- polymixines make holes in cell surface membrane altering its activity
suggest two ways in which the use of antibiotics may be increasing the likelihood of resistance evolving.
- over-prescribing antibiotics
- giving farm animals antibiotics to prevent them from getting infected and reducing business profits
suggest two methods to reduce the likelihood of resistance developing in bacteria.
- minimise antibiotic use
- good hygiene - impact spread of infections
