Immunisation Flashcards
Passive and active are types of what immune response?
Adaptive immune response
What is passive immunity?
The short-term immunity which results from the introduction of antibodies from another person or animal.
What are some advantages of passive immunity?
Gives immediate protection
Is a quick fix
What are some disadvantages of passive immunity?
Short term affect that does not produced immunological memory.
Serum sickness - the incoming antibody is recognised as foreign and results in anaphylaxis.
Incoming immune cells reject the recipient.
Give some examples of passive immunity?
Maternal immunoglobulins can be transferred to foetus via neonatal Fc receptor mechanisms.
Anecdotes for spider, scorpion, snake bites.
What is active immunity?
The immunity which results from the production of antibodies by the immune system in response to the presence of an antigen.
What are some advantages of active immunity?
Long term immunity - immunological memory
Antigen stimulates the response
Faster to respond to a secondary encounter.
What are some disadvantages of active immunity?
No immediate effect.
What is the process of vaccination?
The administration of antigenic material (a vaccine) to stimulate an individual’s immune system to develop adaptive immunity to a pathogen.
What are some common diseases we vaccinate against?
Measles - highly contagious virus causes a rash. Mumps - caused by a virus that can lead to meningitis Rubella Polio Tetanus Flu Shingles Hepatitis A Rabies
Describe vaccines that kill the whole organism?
Target the organism directly
Effective and relatively easy to manufacture
Booster shots likely required
Virus must be heat killed effectively – any live virus can result in vaccine-related disease.
E.g polio
Describe some attenuated whole organism vaccines?
An avirulent strain of target organism is isolated
Can be very powerful and better than killed
Simulate natural infection
Reversion back to virulent form
Refrigeration required.
Describe the outline of the attenuated mechanism?
Virus is isolated and grown in cultured human cells.
Cultured virus is used to infect monkey cells
Virus acquires many mutations that allow it to grow well in monkeys.
Virus no longer grows well in human cells (attenuated) so it can be used as a vaccine.
What are subunit vaccines?
A vaccine which, through chemical extraction, is free from viral nucleic acid and contains only specific protein subunits of a given virus.
What are some advantages of subunit vaccines?
Generally very safe.
Easy to standardise.
What are some disadvantages of subunit vaccines?
Not very immunogenic without an effective adjuvant.
Need to understand how to generate immunity.
What are some examples of subunit vaccines?
Hepatitis B surface antigen
Human papilloma virus proteins
What is a toxoid vaccine?
A bacterial toxin that has been inactivated/suppressed by formalin or heat but still has immunogenicity properties.
What are some advantages of toxoid vaccines?
Toxoid retains antigenicity but has no toxic activity.
What are some disadvantages or toxoid vaccines?
Only induces immunity against the toxin, not the organism that produces it.
What are some examples of toxoid vaccines?
Tetanus
Diphtheria
What are some common vaccine given to travellers?
Hepatitis A Typhoid Neisseria meningitidis serogroups A, C, W135, Y Cholera Yellow fever Japanese encephalitis Tick-borne encephalitis Rabies
What are some contra-indications of vaccines?
Temporary - Febrile illness
Pregnancy (cannot be given live attenuated vaccines).
Permanent - Allergy
Immunocompromised (cannot be given live attenuated vaccines as individuals may develop disease from the vaccine strain).
What is herd immunity?
The resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination.
What are the advantages of herd immunity?
Protects members of the population who can’t be vaccinated e.g pregnant women and the immunocompromised.
What are some factors that make a good vaccine?
Potent antibody response – high antibody titers
Potent CD8+ cytotoxic T cell response
CD4+ T helper response
Memory
What is antigenic shift?
The process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains.
What is antigenic drift?
Mechanism for variation for viruses that occur at point mutations.
