Basic Concepts - 1A Flashcards
Basic concepts of immunity against bacteria?
Activate complement, enhance phagocytosis and inflammation
Virulence factors are produced by bacteria e.g. toxins
Concepts of immunity against viruses?
Neutralising antibodies against viruses
Cell mediated immunity is essential for protection e.g. NK cells and cytotoxic T cells
Interferons are essential
What is a sign of viral infection?
Unusual nucleic acids
What is immunity against helminths?
Th2 immunity helps against parasitic infections
Mast cells and eosinophils with IgE cover and recruit them
Different types of molecules that can be used in vaccines?
Replicating - live attenuated pathogen
Non-replicating - inactivated whole-pathogen
Subunit - toxoids, fragments
Purified antigens - recombinant proteins
Adjuvant - purified antigens + adjuvants
How do adjuvants work?
Engaging pattern recognition receptors
What do epithelial cells act as modulators of?
Immune activation
The presence of what triggers epithelial cells
Presence of allergens
Which cells produce cytokines?
Every cell but macrophages produce 100x more
Do IL1 beta and TLRs signal thorugh same or different pathways?
Same pathway
Where are innate lymphoid cells enriched?
Enriched at barrier surfaces
What are innate lymphoid cells rapidly activated by?
Host-derived cytokines and growth factors
What ILCs are cytotoxic?
NK and ILC1
What ILCs are non-cytotoxic?
ILC2 and ILC3
What is type 1 immunity?
Macrophage activation, cytotoxicity
What is type 2 immunity?
Alternative macrophage activation
For large extracellular parasites and allergens
What is type 3 immunity?
Phagocytosis , antimirobial peptides
For extracellular microbes e.g. bacteria and fungi
What do commensal organisms in the microbiota do to polysaccharides?
Catabolise them to generate short chain fatty acid whihc enhances intestinal epithelial cell barrier function
What do commensal organisms promote production of?
Mucus and the release of antimicrobial peptides such as regenerating islet-derived protein 3gamma from epithelial cells to limit pathogen colonisation and proliferation
What do resident microorganisms in the microbiota inhibit?
The colonisation and/or the proliferation of incoming enteric pathogens
What strategies have enteric pathogens evolved to overcome competition by commensal bacteria?
Killing of commensal competitions through type VI secretion system
Pathogen-induced inflammation, leads to increased epithelial cell turnover
What did fibre that you eat do in mice with allergic responses?
Mice that were fed high fibre diet have more short chain fatty acids and were protected against allergic inflammation in the lung
What are pathological consequences of inflammation?
Autoimmune diseases, sepsis, fibrosis etc.
What are the receptors for C5a and C3 a?
C5a receptor and C3 a receptor
What does binding of C5a and C3 a activate
G protein
Where are mast cells found?
Near small blood vessels in a wide variety of tissues
What do mast cells release?
Substances that alter vascualr permeability such as histamine
What does mast cells binding to C3 a and C5a induce?
Induces degranulation and release of granule contents
What affinity is the binding of IgE to Fc epsylum receptor?
High affinity
When is IgE bound to the receptor?
Always, you can’t detect IgE circulating
What cytokine does mast cells produce?
IL-4
What type of response is producing IL-4?
Th2
What are two effectors functions of NK cells?
Cell killing
Secretion of cytokines
What type of molecules do NK cells recognise changes in?
Changes in expression of MHC I molecules
What is the Fc receptor for?
IgG
What type of affinity is the binding between IgG and Fc receptor?
Low affinity
