L12. Vaccines Theory and Practise 2 Flashcards
What are the differences between active and passive immunisation?
Active immunisation engages the body’s immune system to generate a protective response and immunological memory through vaccination, mimicking a natural infection. Passive immunisation involves the transfer of preformed antibodies, providing immediate but temporary protection without the activation of the body’s immune system or memory generation.
What is the role of the adaptive immune system in active immunisation?
The adaptive immune system’s role in active immunisation involves T and B lymphocytes. T cells are essential for class switching, affinity maturation, and memory generation. Both T and B cells are involved in producing specific responses to antigens, including antibody production.
How does natural passive immunity occur?
Natural passive immunity occurs through the transfer of maternal antibodies (IgG,half life increased by FcRn) across the placenta to the developing fetus, providing the newborn with immediate, albeit temporary, protection against certain infections.
What are the uses of artificial passive immunity?
Artificial passive immunity is indicated for individuals with agammaglobulinemia, those who are immune-compromised, and in situations where there is no time for active immunisation to take effect, such as immediate exposure to a disease with a short incubation period.
What is the principle behind using anti-toxins and anti-venoms in passive immunity, why is this not used as much now?
With some pathogens the main hazard is not the primary infection itself rather it is the effects of very potent toxins released by the bacteria, so antibodies, usually from horse serum, can neutralise the toxins. But now we are usually vaccinated against the pathogen that releases the toxin in the first place.
Give two examples of what anti-toxins are used for?
Tetanus: Clostridium tetani
Botulinum: Clostridium botulinum
Why are toxoids used in active immunisation instead of the pathogens themselves and an example?
Toxoids, which are deactivated toxin derivatives, are used in active immunisation because they can safely trigger an immune response without the risk of disease. For example, the tetanus toxoid vaccine uses an inactivated form of the toxin produced by Clostridium tetani to induce immunity without causing tetanus.
When is prophylactic passive immunisation (passive immunisation) used?
Prophylactic passive immunisation is used as a first line of defense when an individual is accidentally exposed to a pathogen, such as being scratched by an animal, to immediately protect against potential infections.
What are the advantages of passive immunity?
Passive immunity provides immediate protection through pre-formed antibodies, which is crucial when a conventional immune response is too slow, such as with highly virulent pathogens or when no vaccine is available, like in the case of Ebola. It can also be derived from antibodies of surviving patients, although there’s a risk of disease transmission.
What are the drawbacks of passive immunity?
Passive immunity does not activate immunological memory, so it does not provide long-term protection. There’s also a risk of adverse reactions, especially when the antibodies are derived from another species, due to immune responses against these foreign proteins (e.g. serum sickness)
What is the goal of active immunisation?
The goal of active immunisation is to manipulate the immune system to generate a persistent protective response against pathogens by mimicking a natural infection, thereby mobilizing the immune system to create immunological memory.
What are the 4 different types of vaccines used in active immunisation?
Active immunisation can use various vaccine types including whole organism vaccines (live attenuated or killed/inactivated), subunit vaccines (toxoids, antigenic extracts, recombinant proteins, conjugate vaccines), peptide vaccines, DNA vaccines, and engineered viruses.
What are the differences between live attenuated and inactivated organism vaccines?
Live attenuated vaccines use a weakened form of the pathogen that can still replicate, inducing a strong immune response and long-lasting immunity. In contrast, inactivated vaccines use pathogens that have been killed and cannot replicate, generally inducing a weaker immune response and often requiring boosters.
Why are toxoids used in vaccines instead of live toxins?
Toxoids are used because they are inactivated toxins that have lost their harmful properties but still elicit an immune response. They are safe for immunisation, unlike live toxins that can cause disease at very low doses.
Give an example of a live attenuated pathogen vaccine
Vaccine, the bacteria has been cultivated in a medium where it has adapted to survive and has lost the adaptation to survive in the human body.
