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16 Cards in this Set
- Front
- Back
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SIGNALLING IN PRR SYSTEMS |
SIGNALLING IN PRR SYSTEMS |
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In pattern recognition, there are -- cellular recpetors and signalling systems to actiate a response |
few. |
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Give an example of the few receptors and signalling systems producing many antiviral products |
Insects with antimicrobial peptides. - only two receptors are used to switch on two intracellular pathways for many AMPs to be produced. - IMD/relish pathway and Toll pathways are turned on in response to different microbial threats |
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What is interesting about PR signalling systems in mammals compared to insects |
They are preserved - Toll and IMD/relish pathways switched on inresponse to the cytokine TNF |
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PR responses are 1. 2. |
1. rapid 2. transient Zymosan (fungal antigen) causes the secretion of collectins due to tranisent activation of collectin synthesis by haemocytes |
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Why is SIR response complicated?? |
by the variabiity of the system - There are so many receptors so which do you choose to mount an immune response? |
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how is this problem overcome? |
Cloncal selection theory of immunology = the antigen selects the apporproate Ab to destroy it The clonal distrubtion of lymphocytes = the whole lymphocyte population is divided into clones (families) which only express one variant of the hypervariable receptor. The one whos receptor is most appropriate are selected by the antigen to intiate responses that have specificty and memory (clonal selection) |
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How are systems switched on in B cells |
two steps 1. Activation with specific interation with Ag - Ab produced by B cell put on surface. It interacts with an Ab to switch on the B cell. 2. Priming by Th cell - B cell acts as APC. They engulf bacterium and present it to Th cell who gives the final 'go ahead. - MHC 1 or 2???? I think 2?? |
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How are systems switched on in Tcytotoxic cells? |
Same occurs 1. Activation with specific interation with Ag 2. Priming by Th cell - CD4 Th cells produce cytokines for Tc activation |
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What is the result of B cell induction? |
1. proliferation of B cell clones - who can synthesise Ab specific to invading pathogen 2. Differentiaition of Activated B cell clones - become plasma cells who synthesise and secrete specific Ab - changes over course of infection - IgM early, IgG later or - lie dormant as memory cells for immunological memory --> rapid response on second exposure |
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A primary immune response is typified by |
- longer time for induction (1 week) - lower amplitude |
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A seconday immune response is typified by |
- shorter time for induction (3 days) - higer amplitude |
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What is the basis of medical vaccination |
The two hallmarks of Specific Immunological Specificity 1. memory = rapid and powerful 2. Specifity = response to a particular pathogen |
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nice flow chart |
nice flow chart |
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What is an example of similar hypervariable responses in other mammals? |
Tunicates show rejection of tissue transplants - hallmarks of specific immunological memory(just not with T cells) - when tissue was transplanted into a tunicate, lymphocytes destroy the transplanted blood vessels. - a second transplant by the same donor results in a more rapid response - a third transplant by a new donor does not result in a more rapid response |
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What is an example of similar hypervariable responses in other mammals? |
Bacteria-specific responses in bumble bees - bumble bees primed with a specific bacteria showed increased survival against the same species of bacteria but not other bacteria |
