Immunisation Flashcards
What are examples of non-specific immune defenses?
unbroken skin, mucous membrane of gut, lung, acid & enzymes of gut, non-specific metabolism / inactivation
What does innate immunity involve?
complement, WBC & cytokines
Briefly describe the immune response
Primary immune response develops in the weeks following first exposure to an antigen- mainly IgM, secondary immune response is faster and more powerful – mainly IgG
What is ‘passive’ immunity?
Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system
e. g. A newborn baby acquires passive immunity from its mother through the placenta, also breastfeeding
e. g. Immunoglobulin (IG), which contains antibodies pooled together from the blood of many donors, can be injected into a person who needs antibodies.
How long can ‘maternal antibodies’ protect the baby for after birth?
For up to a year against illnesses to which the mother is immune.
What is the only Ig that can cross the placenta?
IgG
What is active immunity?
Active immunity is usually long-lasting immunity produced by the immune system in response to antigens.
Where are the antigens in active immunity from?
These antigens can be from natural infection or from vaccination
What is immunological memory?
The persistence of protection for many years after natural infection or vaccination.
What is an ‘antigen’?
An antigen is defined as “anything that can be bound by an antibody“
Antibodies interact specifically with relatively small parts of molecules. What are these parts called?
These are known as antigenic determinants or epitopes.
What is an antigenic determinant/epitope?
The site of an antigen molecule that interacts with the specific antigen-binding site in the variable region of an antibody molecule known as a paratope.
Antibodies are produced to one specific antigen.
What are the different types f antibody?
IgM, IgG, IgA, IgE
Which antibody is prevalent in the primary immune response that develops in the weeks following first exposure to an antigen?
IgM
Which antibody is prevalent in the secondary immune response?
IgG
how does the 2ary immune response compare to the 1ary?
is faster and more powerful
Which cell produces antibodies?
B lymphocytes
How do antibodies produce immunity?
- Antigen binds non-specifically to variable region of antibody (Ig) molecule. This triggers clonal expansion
- 1st wave of IgM production, followed by IgG production
- IgG binds tightly to antigen and through simultaneous complement binding facilitates the destruction of the antigen-bearing micro-organism
- When infection resolved levels of IgG decline
- One set of the IgG producing B lymphocytes persist with the ability to recognise that specific antigen = Immunological memory
What is HNIG?
Human normal immunoglobulin (HNIg) is made from the plasma of about 1,000 donors. This provides antibodies against many diseases including hepatitis A, rubella and measles.
What is a live vaccine?
Live attenuated vaccines contain whole bacteria or viruses which have been “weakened” (attenuated) so that they create a protective immune response but do not cause disease in healthy people.
What are the advantages of giving a live vaccine?
Single dose often sufficient to induce long-lasting immunity
Strong immune response evoked
Local and systemic immunity produced
What are the disadvantages of giving a live vaccine?
Potential to revert to virulence
Contraindicated in immunosuppressed patients
Interference by viruses or vaccines and passive antibody
Poor stability
Potential for contamination
What type of reactions can vaccines cause?
Local - pain, swelling or redness at injection site; small nodules may form at injection site
General - fever, irritability, malaise, fatigue, headache, nausea, vomiting, diarrhoea, loss of appetite
What is an inactivated vaccine?
Inactivated vaccines contain whole bacteria or viruses which have been killed or have been altered, so that they cannot replicate.
What are the advantages of an inactivated vaccine?
Because inactivated vaccines do not contain any live bacteria or viruses, they cannot cause the diseases against which they protect, even in people with severely weakened immune systems.
What are the disadvantages of an inactivated vaccine?
Do not always create such a strong or long-lasting immune response as live attenuated vaccines.
Need several doses
Local reactions common
Adjuvant needed: keeps vaccine at injection site and activates antigen presenting cells
