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34 Cards in this Set
- Front
- Back
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What is active immunisation? |
Vaccination Administration of an antigen in order to induce active production of immunity and thus protection from disease |
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Give five characteristics of active immunisation |
1. Immunity is specific for the antigen given 2. Immunological memory is induced 3. Immunity involves antibody and/or T cell responses 4. Systemic and/or mucosal immunity can be induced 5. Protection is not immediate |
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What is passive immunisation? |
Administration of pre-formed antibody in order to protect from disease |
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Give the three characteristics of passive immunisation |
1. Protection is immediate 2. No immunological memory is generated 3. No immune response is stimulated in the recipient |
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What is a live attenuate vaccine? |
Organisms whose virulence has been reduced e.g. by repeated culture in vitro |
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How do live attenuate vaccines work? |
The organisms of attenuated virulence multiply in the host, mimicking natural infection but causing no/mild symptoms. The host immune response mimics that generated by natural infection |
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Give three risks of live attenuated vaccines |
Potential for severe infection in immunodeficiency Potential to revert to virulent strain Storage conditions are critical for stability |
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Give three examples of live attenuated vaccines |
MMR BCG Oral polio (Sabin) |
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What are killed vaccines? |
Preparations of whole inactivated virus/bacteria |
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How do killed vaccines work? |
Do not multiply in the host Usually only systemic immunity induced Several doses needed Large amount of antigen required |
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What is the risk of needing to use large amounts of antigen and how can this be overcome? |
Risk of reaction Partly overcome by using adjuvants |
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Three benefits of killed vaccines |
1. No risk of infection (unless faulty inactivation) 2. No risk of reversion to virulence 3. Tend to be more stable for storage |
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What is a problem of using killed vaccines? |
Inactivation may chemically modify structure |
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Give three examples of killed vaccines |
Killed polio (salk) Influenza Pertussis |
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What are subunit vaccines? |
Consist of parts of organisms/products of organisms |
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How do subunit vaccines work? |
Immunisation does not mimic natural infection but induces a response which prevents disease Usually only systemic immunity Several doses needed Adjuvant required |
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Benefits of subunit vaccines |
No risk of infection No risk of reversion to virulence No unwanted components in the vaccine |
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Give four examples of subunit vaccines |
Tetanus toxoid Hep B HiB Group C meningococcus |
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Give an example of a subunit conjugate vaccine and explain how it works |
Meningococcal group C The part of the vaccine from meningococcus (capsular polysaccharide) cannot activate Th cells so by itself is a poor vaccine. It is covalently linked with a diphteria protein that is a strong stimulator of Th cells. |
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What are the contraindications for all vaccines? |
Acute illness Severe allergic reaction to previous dose of the same vaccine |
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What are the contraindications for live vaccines? |
Pregnancy Primary immunodeficiency Secondary immunodeficiency |
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When might vaccines not work? |
1. Live typhoid vaccine given to patient on antibiotics (Ab kill vaccine) 2. Patients receiving immunoglobulin therapy 3. Live vaccines given close together - must be either given at the same time or several weeks apart |
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What are the WHO criteria for immunoglobulin replacement therapy? |
Derived from pooled plasma of at least 1000 donors IgG must be: 1. At least 90% intact 2. Normal ratio of subclasses 3. Biologically active 4. Free of: inflammatory mediators, infectious agents |
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What are the indications for use of immunoglobulin replacement therapy? |
Primary antibody deficiencies: Common variable immunodeficiency, X-linked agammaglobulinaemia, Hyper-IgM syndrome (also in primary T cell deficiencies) Secondary antibody deficiencies: chronic lymphocytic leukaemia or multiple myeloma, HIV, premature infants, early-onset neonatal sepsis |
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What are hyperimmune or specific immunoglobulin preparations? |
Selected for very high titres of antibodies to specific microbes |
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What are hyperimmune immunoglobulin preparations prepared from? |
Plasma pre-screened for high titres of specific antibodies Vaccinated volunteers e.g. rabies immunoglobulin |
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Name some conditions for which hyperimmune immunoglobulin replacement therapy is used |
Hepatitis (sexual, vertical, needle-stick) Rabies RSV (children hospitalised with RSV) Tetanus (susceptible wounds) VZV (babies at risk) CMV (immunosuppressed transplant pts) |
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What are monoclonal antibodies? |
Artificially produced antibodies of a single specificity derived from a single B cell clone |
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Give four biological activities of cytokines |
Stimulation of cells of the immune system Stimulation of inflammation Stimulation of haematopoiesis Anti-viral and anti-proliferative activities |
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What do the anti-viral activities of IFN-a include? |
Inhibition of viral replication and protein synthesis in infected cells Stimulation of the anti-viral immune response |
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When is IFN-a used? |
Treatment of chronic Hep B With Ribavirin for treatment of chronic Hep C |
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Which two factors enhance circulating neutrophil levels? |
Granulocyte colony-stimulating factor Granulocyte-macrophage colony stimulating factor |
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What are the effects of G CSF and GM CSF? |
Reduction in duration of neutropenia and incidence of febrile neutropenia in cytotoxic chemotherapy for malignancy Reduction in duration of neutropenia in myeloablative therapy followed by bone marrow transplant |
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When is interferon-y used? |
In chronic granulomatous disease CGD is primary IF disease involving defects in genes encoding components of phagocyte NADPH oxidase involved in the generation of reactive oxygen metabolites. The activity of NADPH oxidase is up-regulated by interferon-y. |
