Immunology Flashcards
A normal immune response is composed of which three sequential phases?
- Immediate innate immunity- definsins, physical barrier
- Early induced innate immunity- PAMP/PRR interactions, mast cell activation, realise of pro-inflammatory mediators
- Adaptive immune response- activation of naive T and B cells, production of antibodies and antigen-specific cells
What is vaccination?
Deliberate exposure to a pathogen-related antigen to induce immunological mediated response and to acquire immunological memory
What do memory cells allow for?
A rapid response when the same pathogen invades a second time
Symptoms will be eradicated or dampened down in second exposure
Memory cells can remain dormant and reactivate when foreign antigens previously detected are present
Effector cells are more quickly produced this way via clonal proliferation and diffraction of memory cells
What must occur of antibodies to be produced?
An antigen specific cells must be encountered
What is the first antibody produced in response to infection?
IgM
IgM production will change to production of what other antibody class during the adaptive response?
IgG
What is the reason for the change between IgM production to IgG production?
IgG has the same, but added functionality to IgM
What is the lag period?
This is the time when antibody levels are low as they gradually build
Pathogen proliferation is very high at this stage
Symptoms will likely be experienced at this stage
Where do long-lived plasma cell retreat after infection is eradicated and what do they do?
They retreat to the bone marrow
They will secrete antigen specific antibodies for an extended period of time
In a secondary response to an infection, which antibody class(es) are activated from the beginning?
IgG and IgM
How can IgG activate complement?
Via the classic pathway
Why is it often effective to switch to IgA production during the secondary response?
IgA can form dimers which can cross epithelial tissues and that are able to block bacterial attachment to mucous membranes
What is unusual about the immune system combats diphtheria?
The toxin produced by the infection is targeted- not the microorganism
This means the toxin can be cleared, by the individual will still be a carrier
What happens to effector cells (non memory B and T cells) when no antigen is present for binding?
They will undergo apoptosis
Why can memory B cells produce more functional differentiation than in the primary response?
They have already undergone Ig class switching (IgM to IgG) and hypermutation
How are memory cells superior to primary B cell produced ?
- They have already undergone Ig class switching
- They have enhanced cell adhesion
- They have enhanced chemotaxis properties
Why do memory cells encounter antigens faster?
They are present in secondary lymphoid tissues unlike naive cells
This is because they have receptors on their surface which allows for binding with chemokines which causes entrapment within such tissues
What is active immunity?
This is protection obtained solely from an individual’s own immune system and can be stimulated by vaccine or occur naturally
What is passive immunity?
This is temporary immune protection transferred form one individual to another such as secretory IgA in breastmilk
Describe the methodology behind inactivated vaccines?
- These are termed attenuated vaccines
- This involves the vaccine being made up of components that were never alive such and only exist to mimic the real antigen- they can be “edited~” versions of the real antigen
- This will not produce immunity as effective as a live pathogen would
- The the immune response will be mostly B cell mediated and less activity of T cells will be present as a line pathogen is absent
- Immunological memory will likely not last as long and repeat vaccine may be required
Why will there be a relatively weak T cell response to attenuated vaccines?
There are no live components for which T cells can act upon
How can an attenuated vaccine be created?
- Chemical fixatives- the structure can be preserved by formalin
- Heat denaturation
- irradiation
What are the two main problems associated with attenuated vaccine preparations?
- under-inactivation- pathogen is not inactivated correctly and viable pathogens remain present
- Over-inactivation- antigens on over-inactivated pathogens are too difficult from the real pathogen and do not confer immunity against it
What are the main benefits to attenuated vaccines?
- Made quickly
- May elicit good antibody responses
- Easy to store and do not require refrigeration
- Usually safe to give to anyone- even the immunosuppressed
