New immunity content Flashcards
Examples of natural and un-natural passive immunity
Passive immunity exists naturally i.e. the transfer of IgG immunoglobulins from mother to baby or foetus using special Fc receptors or it can be un-natural such as the artificially immune cells that are given to a person who has just had a toxic snake bite etc.
What is active immunity ?
Produced by host own immune system in a response to infection or exposure or immunisation
Takes weeks to develop
Immunological memory cells produced providing long term immunity
Protection is permanent
What is passive immunity?
Transfer of Abs (i.e. the transfer of IgG through the placenta) or in the colostrum (first milk for a baby), cells from other individual, immunoglobulin therapy
Immediately
No memory cells and may be rejected by the body causing serum sickness or anaphylaxis.
Protection temporary
What is a vaccination?
A method of creating active immunity by transferring antigenic material to stimulate the hosts immune system to develop an adaptive immunity to the pathogen. If a patient is pregnant, febrile, has certain allergies or is immunocompromised then some vaccines may not be suitable.
What are the different names of the different vaccines?
Live attenuated
Inactivated
Toxoid
Subunit
What is a live attenuated vaccine?
Live Attenuated (LAV) which is where the pathogenetic virus is isolated from a patient and grown in human cultured cells. The cultured virus is then used to infect monkeys causing the virus to acquire many mutations. This new mutated form is then given to humans as it no longer causes infection. (These cannot be given to the immunocompromised)
What is a inactive vaccine?
Inactivated which used a killed antigen.
What is a toxoid vaccine?
Where toxin is treated with formalin which means that toxin retains antigenicity but has no toxic activity.
What is a subunit vaccine?
Subunit where recombinant proteins are used. This is generally safe and easy to standardise
What is herd immunity?
vaccination coverage of a population of 90-95%.
What makes a good vaccine?
A good vaccine is potent which means it has a high antibody response, induces a high CD8+ cytotoxic T and CD3+T helper cell response, and creates memory.
What are the challenges in vaccine creation ?
creating persistent memory, antigenic shift (changing genetic of pathogen over time) and drift (point mutation) and the cold chain network (getting the vaccine from the lab to all patients).
What is an autoimmune disease?
An autoimmune disease is the failure or breakdown of the immune system as a result of intolerance to something natural and normal. They can be a result of environmental or genetic factors. They can be organ specific or systemic. I.e. Lupus erythematosus is a systemic condition while Type I Diabetes is a organ specific autoimmune disease.
How are autoimmune diseases treated?
Autoimmune disease are usually treated with blanket immunosuppression however that has nasty side effects. They can also be treated with more selective treatments which is a better approach. Treatment is rarely able to cure these conditions however.
Type I Hypersensitive
This is the cause of most allergenic reactions. It occurs when genetic variations give rise to receptors on the surface of T cells which can bind to things they otherwise would be able to i.e. pollen. This binding causes the production of specific antibodies which go and bind to all the other pollen and cause a big response.
