12.7 - Preventing & Treating Disease Flashcards
What is natural active immunity?
Natural active immunity: Immune response which results in a response from the body to the invasion of a pathogen
- Body meets pathogen for first time, antibodies produced, body stores T-,B- memory cells for a heightened secondary response.
- It is active because the body has acted and produced antibodies/memory cells
What is natural passive immunity?
Natural passive immunity: Immunity given to an infant mammal by the mother through the placenta and the colostrum (first milk produced at birth)
- Baby’s immune system is not mature at birth, cannot produce antibodies, relies on mother.
- Antibodies cross through placenta – gives baby some immunity at birth.
- First milk is colostrum, high in antibodies.
- Infant gut allows the glycoproteins to not be digested > giving the infant the same level of immunity as its mother.
- Lasts until a baby can make its own antibodies.
Why is artificial immunity needed?
Some diseases kill before the body can respond and make antibodies
What is artificial passive immunity?
Artificial passive immunity: Immunity that results from administration of antibodies from another animal against a dangerous pathogen
- For fatal diseases, antibodies formed in one individual, extracted, and injected into the diseased
- Gives temporary immunity
- Doesn’t last long, is life saving
How does artificial active immunity work?
Artificial active immunity: Immunity which results from exposure to attenuated form of pathogen, by vaccination
- Body’s immune system stimulated to make antibodies.
- Pathogen is made safe, so antigens are intact, but not harmful (no risk of infection)
- Vaccines contain: killed, inactivated bacteria/virus
- Attenuated (weakened strains of bacteria/viruses)
- Detoxified/altered toxins
- Isolated antigens from pathogens
- Genetically engineered antigens
- Vaccine – small number of safe antigens, injected
- Primary immune response triggered by foreign antigens. Produces antibodies and memory cells
- If you encounter the pathogen again, secondary response will be quicker.
How do vaccines help with pandemic and epidemics?
Vaccines give long term immunity to disease. Also used to prevent epidemics (rapidly spreading communicable disease on a local/national level. Pandemic (same as epidemic, but on an international level.
What is herd immunity?
Herd Immunity: When a significant number of people in the population have been vaccinated, this gives protection to those who don’t have immunity.
Give examples of communicable diseases that can’t be prevented on an international level
- Malaria (Plasmodium) very evasive, spends time in erythrocytes so it is protected by self antigens of immune system
- HIV – enters macrophages and T-helper cells, disabling the immune system.
Give examples of natural sources of medicines
Microorganisms and plants produce range of molecules beneficial as medicines
E.g.
-
Penicllin - extracted from mould on melons
- Is an antibiotic
-
Digoxin - extracted from foxgloves
- Drug used to treat atrial fibrillation and heart failure
Why are plants and microorganisms important in medicines?
- Source of many medicines
- Every organisms could potentially hold a cure to pathogens and diseases without cures now (e.g. cancer)
- Important to maintain biodiversity, otherwise a potential life-saving cure may go extinct
What is pharmacogenetics?
- Process of assessing how an individual’s genome will respond to different drug action
Personalised medicine is screening an individual’s genome to identify genetic disorder and develop a treatment personalised to that individual
What is synthetic biology?
- Using genetic engineering to develop new medicines or molecules for use in biology
- E.g. making new enzymes to produce a new product or altering natural enzymes to produce a new effect
- E.g. nanotechnology - using tiny, non-natural particles to deliver drugs to specific sites within cells of tumours or pathogens
What are the pros and cons to using antibiotics to treat bacterial infection?
PROS
- Selective toxicity - inteferes with bacterial metabolism and not with somatic cells
CONS
- Bacteria can randomly develop a mutation causing resistance to antibiotics
-
Natural selection of resistant bacteria when antibiotic is next applied
- Causes population with mainly antibiotic-resistant bacteria
- Farmers feed animals antibiotics to increase yield and profits, this accelerates bacterial natural selection
- When consumers eat meat, the resistant bacteria are passed on
Give 2 examples of antibiotic-resistant bacteria
MRSA
Clostridium difficile
