Immunisation Flashcards
Outline the types of active immunity.
- Natural: Infection or exposure
- Artificial: Vaccination
Outline the types of passive immunity.
- Placental transfer of IgG, colostral transfer of IgA
- Immunoglobulin therapy or immune cells
Describe how Active Immunity works and its effect.
- Antigen stimulates the immune response.
- There is no immediate effect but it produces a faster and better response to the next antigenic encounter.
- It gives long term immunity and an immunological memory is created.
Describe how Passive Immunity works and its effect.
A person is given antibodies to a disease, rather than producing it themselves through his or her own immune system.
What are the advantages and disadvantages of Passive Immunity?
It gives immediate protection.
However, it has a short term effect and no immunological memory is created.
- SERUM SICKNESS- incoming antibody is recognised as a FOREIGN antigen by the recipient and results in anaphylaxis.
- Graft vs host disease (cell grafts only)- incoming immune cells reject the recipient
What are examples of passive immunity?
Natural: Maternal immunoglobulins can be transferred to the foetus or neonate naturally using a specialised mechanism involving the neonatal Fc receptor.
Artificial: Snake + spider bites, scorpion + fish stings. Passive infusion of antibody SPECIFIC for the TOXIN occurs.
Define vaccination.
The administration of antigenic material (i.e. a vaccine) to stimulate an individuals immune system in order to develop adaptive immunity to a pathogen.
What are the types of vaccinations?
-Inactivated/killed antigen vaccines
-Attenuated whole organism vaccines (mainly viruses)
-Subunit vaccines (purified antigen)
Toxoid vaccine (modified toxin)
Describe, in detail, inactivated/killed antigen vaccine.
And example?
- The target organism is killed.
- It is effective and relatively easy to manufacture.
- However, Booster shots are likely required.
I.e. polio virus
Describe, in detail, attenuated whole organism (mainly viruses) vaccines.
And example?
- A VIRULENT strain of target organism is ISOLATED.
- It can be very powerful and better than killed.
- It stimulates a natural infection and reverts back to virulent form and refrigeration is required.
I.e. circulating vaccine derived polio virus (cVDPV)
Describe, in detail, subunit vaccines (purified antigen)
And example?
-Recombinant proteins.
Advantages-Generally is very safe and easy to standardise.
Disadvantages- It is not very immunogenic without an effective adjuvant and you need to understand how to generate immunity.
I.e. HPV.
Describe, in detail, toxoid (modified toxin) vaccine.
And example?
The toxin is treated with formalin.
The toxoid retains antigenicity but has no toxic activity.
Disadvantage: This only induces immunity against the toxin and not the organism that produces it.
I.e. tetanus, diphtheria.
What makes a good vaccine?
A vaccine with:
- A potent antibody response with high antibody titers
- Potent CD8+ cytotoxic T cell response
- CD4+ T helper response
- Immunological memory
What are the challenges facing vaccines?
- Conventional vaccines cannot elicit immunity against all infectious disease
- Persistence- vaccines should ideally have a life-long protection
- Generation of memory cells
- Protection of vulnerable groups i.e. the very young, elderly and immunocompromised
- Antigenic shift and drift, strain diversity in general
Outline the relationship between vaccines and immunotherapy.
Immunotherapy: Type of cancer treatment that boosts the body’s natural defences to fight cancer.
Possible prospects of post-tumour immunisation?
