Immunity Flashcards
Immunity
Resistance to infection by invading micro-organisms, Depends on the presence of antibodies and memory cells (B and T)
4 types of immunity
Natural or artificial, passive, active
Natural immunity
Occurs without human intervention (no injection)
Artificial immunity
Giving people an antigen or an antibody (human intervention, injection)
Passive immunity
when a person is given antibodies produced elsewhere (short-lived as eventually killed off, takes a short time), can be natural such as antibodies in breast milk, or artificial such as anti-venom and tetanus antibodies
Active immunity
results from exposure to the antigen causing the individual to produce its own antibodies (go through immune response- long lived but takes a long time), Natural- after you have suffered from the disease such as chicken pox, Artificial- vaccinated against measles (given antigens)
Immunisation/vaccination
Artificial introduction of antigens into the body so that the organism develops the ability to produce the appropriate antibodies without having to suffer the disease
Vaccine
Antigen preparation (attenuated(weakened through temp, chemicals or UV light) antigens) used in immunisation
How can vaccinations be given
Injections, Orally, Nostril spray, Skin patches, Genetically engineered plants
5 types of vaccine
Attenuated, inactivated, toxoids, sub-units, recombinant DNA
Attenuated vaccine
Created from a micro-organism that has a reduced virulence, E.g exposing an antigen to a high temperature, polio vaccine
Inactivated vaccine
Created from dead micro-organisms, cholera or whooping cough vaccine
Toxoids vaccine
Created from inactivated toxins produced by bacteria, tetanus vaccine
Sub-units vaccine
Created from fragments of dead organisms, hepatitis B vaccine
Recombinant DNA
Changing DNA of micro-organisms, inserting DNA sequences
Herd immunity
High proportion of population is immune to disease
Vaccine programs
Effective vaccine programmes meaning the incidence of disease decreases which can lead to a failure to vaccinate and a loss of herd immunity (E.g whooping cough, polio)
Childhood vaccines
Aren’t compulsory but 90% of infants are vaccinated by 12 months of age (very young babies can’t be vaccinated as the mother’s antibodies destroy the vaccine contents)
Risk to vaccination
Allergic reactions to the medium in which the attenuated antigen is carried (such as egg yolk which can be used to grow viruses), Introduction of cross-species contamination, Dangerous chemicals used in manufacture
Socio/cultural and economic ethical concerns of vaccinations
How the vaccine was manufactured, tested on animals and it’s risk to health- negative side effects (E.g rubella vaccine is manufactured using cells from an aborted foetus, HIV vaccine testing on humans), Encourage vaccinated teenagers to be sexually active, Right of the parent to vaccinate, Some religions oppose immunisations, Cost of vaccines may not be affordable (other countries without Medicare), Interests of commercial enterprise that manufacture the vaccine can affect its use (3 companies made COVID vaccines)
What does the hygiene hypothesis say
Child’s environment can be “too clean”, Lack of exposure to germs doesn’t give the immune system a chance to develop resistance to diseases
Why is the hygiene hypothesis true
Less exposure to bacteria and viruses means no immune response is triggered, no memory cells are present increasing the chance of being infected, results in overproduction of histamine leads to allergies
What are antibiotics used for
Used to fight infections of micro-organisms (usually bacteria), Not effective against viruses
How do antibiotics work
Work by blocking translation (when amino acids are joined together, can’t reproduce) during protein synthesis of bacteria, Can work on a wide range of bacteria or specific types (Broad or narrow spectrum)
Two types of antibiotics
Bactericidal and bacteriostatic
Bactericidal antibiotics
kills bacteria by changing or damaging the structure of their cell wall, allowing their contents to leak out
Bacteriostatic antibiotics
stop bacteria from reproducing by blocking protein synthesis
Overuse of antibiotics
Research suggests that overuse caused evolution of generations of drug resistant bacteria meaning doctors should start considering giving multiple anti-biotics at once to decrease the likely hood of some bacteria resisting and staying alive
Antibiotic resistant bacteria
Resistance occurs as each type of bacteria can be resistant to a different anti-biotic. If you are only given one anti-biotic at a time, it increases the likely hood of one bacteria being resistant to it. If you are then given a second anti-biotic, it could kill the type of bacteria that survived the first but another type of bacteria could be resistant to the second anti-biotic. The same thing could happen when given a third anti-biotic resulting in bacteria surviving all three anti-biotics when taken separately.
Antivirals
Drugs which inhibit the action of viral pathogens
How do antivirals work
Work by targeting specific proteins and disabling them or inhibit the life cycle of the virus, Enhance the body’s immune system to attack the virus
