vaccination and the autoimmune response Flashcards
Active immunity
Antigen enters the body, your immune system responds, protection often lasts a lifetime
Natural active Immunity
occurs when your naturally exposed to the antigen
Artificial active immunity
provided with vaccine that contains one or more antigens
Passive immunity
Person receives antibody from another person without being exposed to the antigen, no immune response occurs
Natural passive immunity
antibodies cross placenta during pregnancy and through breastmilk when the child is born. Child only received antibodies to antigen that the mother has built immunity against
Artificial passive immunity
antibodies are injected or transfused into a person to provide them with instant immunity; e.g. injection of antitoxin if a person is suspected to have rabies or tetanus
Vaccination
when vaccine is administered to you usually by injection
Immunisation
what happens in your body after you have the vaccination
How does vaccine work?
Vaccines contain antigen
Cells in the immune system recognise the antigen as non-self and attack them
Once the primary specific immune system response has run its course, memory cells are produced that will recognise the antigen if they ever come across it again
If a person is infected with that highly specific pathogen, memory cells will produce many plasma cells that release antibodies
The antibodies will bind to the antigens on the pathogen and neutralise them before the pathogen can make you sick
What is in the vaccine?
Whole, live microorganisms with very similar antigens to the real pathogen e.g. smallpox vaccine uses a similar virus that causes cowpox
A harmless or attenuated version of the pathogen
A dead pathogen
A preparation of the antigens (or mRNA for antigens) from a pathogen
A toxoid (harmless version of a toxin)
Herd immunity
almost all people in a community must be vaccinated
The disease then becomes extremely rare
Those who are unable to be vaccinated or choose not to are protected
This allows the prevention of epidemics – mass outbreaks of disease
Routine vaccines
MMR – measles, mumps and rubella – usually given to children at 1 year and then again just before they start school, vaccine contains attenuated measles, mumps and rubella viruses
Meningitis C vaccine – protects against the bacteria that causes meningitis C, given as an injection to babies at 3 months, booster to 1 year-olds and then again during the teen years
Polio vaccine – usually given orally
Antigenic variation
When pathogen mutate and change their surface antigen/proteins and a new strain is formed
problems with antigenic variation
if exposed to the pathogen again, memory cells from the first infection will not recognise the different antigens
Immune system will have to carry out primary immune response again
Makes it difficult to develop vaccines against some pathogens e.g. HIV, influenza and covid-19
Epidemic
an infectious disease spreads rapidly to a large population
Pandemic
an infectious disease spreads rapidly globally
Autoimmune disease
Abnormal immune response that occurs when antibodies start to attach self-antigens
Attack may be aimed at a single organ, a system or the whole body
A blood test would show antibodies present for your own antigens
Rheumatoid arthritis
Caused by cells of the immune system attacking cells in the joints
Causes pain and inflammation
Joints are gradually degraded
Constant pain
Person feels fatigued and movement is difficult
What causes autoimmune disease?
Genetic factors, autoimmune disease can be inherited
Environmental factors, the prevalence of these diseases in the developed world
Ppl who moved from rural areas to urban areas
Sources of medicines
Accidental discovery e.g. penicillin
Traditional remedies e.g. willow-bark and aspirin
Observation of wildlife e.g. bears use citrus oils as insecticides and antiseptics
Further plant research e.g. natural chemicals as potential medicines
Research into disease-causing microorganisms e.g. to block virus entry into cells
Personalised medicine
cancer drugs<– soil bacteria
Daffodils –> alzhemiers
Future of drug discovery
Biodiversity is rapidly being lost throughout the world, including the rain forests and coral reefs
At least partly due to human activities
Very important to maintain biodiversity as a plant, animal or microorganism could be the key to a life-saving drug
Medicines
Can be used to treat both communicable and non-communicable diseases
Painkillers
Anti-inflammatories
Anti acid medicines (reduce indigestion)
Chemotherapy
Antibiotics
Antifungals
Sources of medicine
Penicillin
Antibiotics
Personalised medicine
Penicillin
First widely used, effective, safe antibiotic
Comes from a mould
Discovered by alexander fleming in 1928 (20th century)
Steadily became routinely used medicine
Antibiotics
Interfere with the metabolism of bacteria without affecting the metabolism of human cells
Therefore inhibit growth or kill bacteria (selective toxicity)
Antibiotics can cause side effects and even severe allergic reactions
Personalised medicine
Your genes determine how your body responds to certain drugs
Some drugs are more effective for some people than others
Personalised medicine are tailored to a persons’ individual DNA, doctors could look at your genetic information to predict how you would respond to different drugs and only prescribe the one that is effective for you
antibiotic resistance
Genetic variation in population of bacteria due to mutation
Mutation may allow resistance to an antibiotic
Those without the gene for resistance die – removing competition
Those with advantageous allele, survive and reproduce
Allele becomes more common in population
MRSA
Bacterium carried by up to 30% of the population on skin or in the nose
Cause boils, abscesses and potentially fatal septicaemia
Was treated effectively with methicillin before but a mutation produced methicillin-resistant strains
C.difficile
Bacterium in the guts of about 5 % of the population
Produces toxins that damage the lining of intestines, leading to diarrhoea, bleeding or even death
Not a problem for a healthy person but when commonly used antibiotics are used, the helpful gut bacteria are killed and the pathogen survives and takes hold rapidly
