3.7 Nerobiology and immunology Flashcards
Explain the process of vaccination (1)
This is normally done through vaccination by injection or ingestion of antigens from the disease pathogen
describe the process of vaccination.
Vaccination is a process that involves the introduction of antigens from a pathogen to an individual in order to stimulate the production of B-lymphocytes with specific receptors to create specific antibodies
Explain the process of vaccination (2)
The vaccinated individual then has vaccination immunity because when they encounter the ‘real’ pathogen, they will not suffer from symptoms of disease because their immune system already has lymphocyte memory cells that are able to quickly respond to destroy the infectious pathogen.
Identify the sources of antigen that can be used in vaccine production.
The antigens used in vaccines can be :
· inactivated pathogen toxins e.g. tetanus toxoid
· dead pathogens e.g polio
· parts of pathogens e.g.HPV
· weakened pathogens e.g. mumps, measles and rubella.
State the purpose of adding an adjuvant to a vaccine
Antigens are usually mixed with an adjuvant e.g. aluminium slats, when producing the vaccine. The adjuvant is a substance which makes the vaccine more effective by enhancing the immune response.
Explain the term ‘herd immunity’.
Herd immunity occurs when a large percentage of a population is immunised and this results in any non-immune individuals being protected by being part of the herd as there is a lower probability they will come into contact with infected individuals
Whats the positives in establishing herd immunity
Establishing herd immunity during vaccination programmes is very important in reducing the spread of diseases.
E.g. Herd immunity thresholds for examples of global diseases
Identify the three main factors involved in determining the herd immunity threshold.
The herd immunity threshold for a disease depends on the :
· type of disease
· effectiveness of the vaccine
· density of the population.
Explain the term ‘mass vaccination programme’ and the difficulties that can arise. Advantages
A mass vaccination programme is a planned programme of vaccination within the population that is designed to establish herd immunity to a disease.
The World Health Organisation (WHO) successfully implemented a mass vaccination programmes for smallpox which led to global eradication of the disease.
Disadvantages to mass vaccination programme
However, mass vaccination programmes are not easy to implement as difficulties can arise when widespread vaccination is not possible due to poverty in the developing world or when vaccines are rejected by a percentage of the population in the developed world.
Explain the term ‘antigenic variation’
Antigenic variation is a feature of some pathogens where they are able to change their antigens. This means that memory cells are not effective against these pathogens
State the role of antigenic variation in influenza.
Rapid evolution due to mutations such as substitutions, deletions, and insertions, produces the antigenic variation that is seen in influenza viruses.
State the impact of antigenic variation in influenza.
This makes influenza an extremely efficient virus as it rapidly evolves to evade the memory cells of the immune defence system. This is why the influenza virus remains a major public health problem and why individuals who are at greatest risk require to be vaccinated every year with the latest form of the influenza vaccine.
