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30 Cards in this Set
- Front
- Back
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What are the aims of vaccination?
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- The aims of vaccination are to induce memory inT and/or B lymphocytes through the injection of a nonvirulent antigenpreparation.
- Thus, in the event of an actual infection, theinfectious agent and/or its toxin is met by a secondary rather than a primaryresponse. - Thetiming of vaccination depends on the likelihood of infection; vaccines againstcommon infections being given as early as possible, allowing for the fact thatsome vaccines do not work properly in very young infants. |
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What is smallpox?
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Acute contagious disease caused by the variola virus, amember of the orthopoxvirus family.
It was one of the world's most devastating diseases known tohumanity. It was declared eradicated in 1980 following a global immunizationcampaign |
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How is smallpox transmitted?
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Smallpox was transmitted fromperson to person via infective droplets during close contact with infectedsymptomatic people
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What are the two forms of smallpox and what is their significance?
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Two forms of small pox – a major and a minor form which wasmuch milder.
If the minor form was caught the individual then becameimmune to catching the major form. For this reason people were made to inhalethe pus from people with smallpox to contribute to herd immunity |
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What is immunogenicity?
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Immunogenicity is the ability of a particular substance, suchas an antigen or epitope, to provoke an immune response in the body of a humanor animal. It is the ability to induce a humoral and/or cell mediated immuneresponse.
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What are the requirements for immunogenicity?
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1) The material must be foreign and recognised asnon self
2) It must have a high molecular weight as the bodygenerally doesn’t make antibodies for small substances 3) It must be chemically complex |
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What are the branches of the immune system?
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Immunity is either passive or active, what do these refer to?
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Passive:Immunity produced bythe transfer of antibodies to someone that were produced by another person or avaccine. Protection from passive immunity diminishes in a relatively shorttime, usually a few weeks or months. Passive immunity also means that the individualhasn’t had to develop an immune response thus there will be no memory. - Active: This is acquired when anindividual themselves is exposed to a pathogen and develops an immune response.
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What is natural and artificial immunity of the passive immune system?
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Natural: Antibodies passed from themother to the baby before birth confer passive immunity to the baby for thefirst 4-6 months of life.- Artificial: Injection of preformedantibodies however this may be hazardous as the body may then developantibodies to the injected antibody.
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What are the natural and artificial branches of active immunity?
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Natural: The individual comes across a pathogen withinthe environment and is exposed to it causing an infection and an immuneresponse
Artificial: The individual isinduced by a vaccine, a substance that contains the antigen. which stimulates aprimary response against the antigen without causing symptoms of the disease. |
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There are two different types of immune responses. What are these?
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1) Primary immune response
2) Secondary immune response |
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What is primary immunity?
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On first exposure to an antigen, a primaryimmune response develops resulting in production of IgM antibodies. This isusually followed by an IgG immune response within 4–5 days. This response isself-limiting and will stop when antigen is no longer available to stimulate Bcells.
This type of immunity has no memory thus acts the same way regardless of the microorganism it is presented with. The result is not very strong. |
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What is secondary immunity?
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When antigen is reintroduced, there are moreantigen-specific B cells, which have differentiated to more responsive memory Bcells, resulting in a more rapid response usually in IgG antibodyproduction. The secondary immuneresponse is more rapid than the primary – it is so great that the individualdoesn’t actually get to the disease state /get any symptoms.
The main immunoglobulin molecules of the secondary response are IgA, IgD and IgE. |
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What are the features of an organism that make it a good candidate for a vaccine?
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Small: Having a small genome
Nosecondary host: Makes them good because if there is only a human host and80% of them have been vaccinated and are immune this produces herd immunity. No escapemechanisms |
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What is the variola virus?
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Virus with an enveloped, biconcave core with two lateralbodies, brick shaped to pleomorphic virions
Causes Smallpox Exposure routes: Inhalation of large airbornerespiratory droplets usually through close contact. Lower transmissibility fromfomites or contact with infectious material in scabs.· |
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Is there any chemotherapeutic agents available for small pox?
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There is no specific chemotherapeutic agent for smallpox. Antibiotics may be used for coincident secondary infections, and vaccinia immune globulin may modify the disease course stats
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What are some key features of the HIV virus?
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- Moredifficult to develop vaccine for this due to the GP120 proteins which help todisguise the fact that it is foreign
- HIV virus requires reverse transcriptase forreplication - Mutations occur at a regular rate so there arelots of different variations within any one host also making it hard to treat -It infects CD-4 T helper cells which arerequired for the immune response. |
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What are some key features of the influenza virus?
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- Commonly known as theflu
- Influenza virusesare RNA viruses that make up three of the five genera of the family Orthomyxoviridae, InfluenzavirusA, B and C. · - The hemagglutinin (HA) andneuraminidase(NA)proteins are shown on the surface of the particle. |
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What features make a good vaccine?
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- Should activate antigen processing andproduction of cytokines
- Memory T and B cells should be produced · - Stimulating antigens should be persistent inlymphoid tissue- prolonged exposure will bring about a response· - Shouldnot cause any adverse reactions. |
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There are three different types of vaccinations what are these?
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- Killed organisms
-Live attenuated organisms - Sub unit vaccines |
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What is a killed organism vaccine?
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Vaccineprepared from dead microorganisms used to provide immunisation from organismsthat are too virulent to be used in the living attenuated state, as they aredead they cannot replicate. The immune system reacts to the presence of thepathogen in the same manner as usual, however when it is live the immunityproduced is usually more effective.
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What is a live attenuated vaccine?
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Vaccines prepared from live microorganisms /functional viruses whos disease producing ability has been weakened but theirimmunogenic properties have not.
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What are subunit vaccines?
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Partsof a particular organism are injected into the individual. They present an antigen to the immune system without introducing viralparticles, whole or otherwise
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What is polio?
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- Caused by viral infection
-Attacks part of the spinal chord -Infection is spread through stools, coughing orsneezing -30% make a complete recovery -30% mildparalysis, -30% sever / moderate paralysis -10% die due to breathing /swallowing difficulties as the diaphragm is affected. |
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What are attenuated viruses?
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- Select for a virulent strain but are much weaker
- Cultured under suboptimal conditions - Requires a single booster – After that there is life long immunity - Less stable Produces humoral and cell mediated immunity |
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What are the dangers of attentuated vaccinations?
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- May revert to the virulent form
- Patients who are immunocompromise: cannot fight offinfection |
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What are inactive vaccinations?
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- Killed by chemicals / gamma rays
- Requires multiple boosters - More stable Produces only humoral immunity - Cannot revert to the virulent form |
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What is herd immunity?
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- A form of immunity that occurswhen the vaccination of a significant portion of a population / herd(>80%) provides a measure ofprotection for individuals who have not developed immunity.
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What are recombinant vector vaccines?
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- Recombinant vector vaccines are experimental vaccines similar toDNA vaccines, but they use an attenuated virus or bacterium to introducemicrobial DNA to cells of the body. “Vector” refers to the virus or bacteriumused as the carrier.
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In nature, viruses latch on to cells and inject their genetic material into them. How have scientists have taken advantage of this process?
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They have figured out how to take the roomy genomes of certainharmless or attenuated viruses and insert portions of the genetic material fromother microbes into them. The carrier viruses then ferry that microbial DNA tocells. Recombinant vector vaccines closely mimic a natural infection andtherefore do a good job of stimulating the immune system.
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