principles of immunisation Flashcards
what are the different types of immunity
immunity is either adaptive or inate
adaptive immunity can be active or passive
active immunity can be natural (infection or exposure) or passive (immunisation)
passive immunity can be natural (placental transfer of IgG or colostral transfer of IgA) or passive (immunoglobulin therapy or immune cells)
advantages passive immunity
immediate protection quick fix
disadvantages of passive immunity
- short term effect - no immunologcal memory - serum sickness - incoming antibody is recognised as a foreign antigen by the recipient resulting in anaphylaxis - graft vs host disease (cell grafts only) - incoming immune cells reject the recipient
natural passive immunity example
maternal immunoglobulins can be transferred to the foetus or neonate naturally using a specialised mechanism involving the neonatal Fc receptors
artificial passive immunity examples
snake or spider bites, scorpion or fish stings: passive infusion of antibody specific for the toxin. Hypogammaglobulinemia: 1y/2y infusion of gamma-globulins to reduce infection. Rabies immunoglobulin: post-exposure prophylaxis together with vaccination
where can immunoglobulin be used for post-exposure prophylaxis
- Human normal immunoglobulin (HNIG): Hep A, measles, polio, rubella - Specific immunoglobulins: Hep B, rabies, tetanus, varicella-Zoster virus
active immunity types
Natural - exposure/infection, artificial - vaccination
what stimulates active immunity
- Antigen (whole organism or part of it) stimulates immune response
what are some of the benefits of active immunity
- Long term immunity - may be lifelong - Immunological memory - No immediate effect, faster and better response to next antigenic encounter
how is immunisation related to active immunity
The administration of antigenic material (a vaccine) to stimulate an individual’s immune system to develop adaptive immunity to a pathogen
name 3 common diseases vaccinated against
measles, mumps and rubella MMR vaccine
what are the 4 types of vaccines
killed whole organism, attenuated whole organism, subunit vaccines, toxoid vaccines
what are killed whole organism vaccines
target organism (e.g. polio virus) is killed (must be completely killed in order to be effective and not cause disease) effective and relatively easy to manufacture booster shots likely to be required,
what are attenuated whole organism vaccines
(mainly viruses): an avirulent strain of target organism is isolated can be very powerful and better than killed vaccines, stimulate natural infection, reversion back to virulent form is possible refrigeration required
what is circulating vaccine derived polio virus
Acute paralysis derived from the vaccine-virus which genetically mutates into a form that can paralyse, occurs in seriously under-vaccinated populations where the excreted vaccine-virus can circulate for an extended period of time