Flashcards in *Immunology 1 (lectures 1 and 2) Deck (63):
What is it?
Severe combined immunodeficiency
Severe abnormalities of the immune system
5 things caused by the immune system going wrong?
6 causes of emergence of new infections?
change in human behaviour
changes in dynamic of other infections
loss of natural habitat
Interactions of pathogens with humans e.g. resistance
What exists between pathogens and hosts
Evolutionary arms race
Where do pathogens infect the body through?
Mucosal surfaces (airway, GI tract, repro. tract)
External epithelia (wounds, insect bites, etc.)
5 components of the body that protect against infection?
How does the skin protect against infection?
Physical barrier (highly packed, highly keratinised, multilayered cells)
Physiological barrier (low pH (5.5), low O2 tension)
Sebaceous glands (secrete hydrophobic oil, lysozyme (destroys bacterial cell wall), ammonia (anti-bacf. properties), defensins (anti-microbial peptides))
What does mucous line
All cavities that come into contact with the environment e.g. resp, GI, urogenital
How does mucous prevent infection?
contains enzymes (lysozyme, defensins)
Contains lactoferrin (starves invading bacteria of iron)
what do cilia do
Directly trap pathogens
aid in the removal of mucous
How does commensal bacteria help to prevent infection?
Competes with pathogenic microbes for scarce resources
Produces fatty acids and bactericidns
reduce pH in large bowel
Synthesise vitamin K and B12
What is bactericidin
An antibody that causes complement dependent lysis of bacteria
What does eradication of normal flora by board spectrum antibiotics often cause?
Live bacteria and east that are good for your health
Network of specialised cells, tissues and soluble factors that co-operate to kill and eliminate disease-causing pathogens and cancer cells
4 classes of pathogen
Extracellular bacteria, parasites, fungi
Intracellular bacteria, parasites
Parasitic worms (Extracellular)
See mind map study material for info about components of the immune system
Any substance that can stimulate an immune response
Family of approx. 30 different proteins
Where is complement produced?
In the liver
What do antibodies provide defence against?
Extracellular pathogens and toxins
Where do complement proteins become activated?
infected/ inflamed tissues
What do complement proteins have the ability to do?
enzymatically cleave and activate other downstream complement proteins in a biological cascade
Name for chemical messanger
Summarised role of cytokines
co-ordinates the immune system
4 examples of cytokines?
Interferons, tumour necrosis factor, chemokines, interleukins
Tumour necrosis factor
Control and directs cell migration
Various functions e.g. inflammatory mediator, stimulate T lymphocytes to become NK cells
Monocytes, macrophages, neutrophils (ingest bacteria and fungi and clear debris from the body
What is an important source of cytokines which regulate acute inflammatory response?
Where do monocytes differentiate into macrophages
in peripheral tissues
what are macrophages
Long lived tissues resident phagocytes
What are the functions of macrophages
to clear cellular debris and engulf and kill pathogens
Where are kupffer cells located and what is their function
Location of alveolar macrophages
location of mesangial cells
location of microgal cells
Additional functions of macrophages (3)
involved in tissue repair and wound healing
involved in antigen presentation
Other name for neutrophils
Less than 6 hours (short)
Where are neutrophils found?
Circulate the blood and are rapidly recruited into inflamed, damaged and infected tissues
How do dendritic cells work?
Present in peripheral tissues where they are in an immature state
They phagocytose an antigen
Then mature and migrate into secondary lymphoid tissue where they play a key role in antigen presentation
Which carries out more killing and degradation compared to antigen presentation, neutrophils or macrophages?
Where are mast cells found?
protect mucosal surfaces
Where are basophils and eosinophils found
circulate in blood and are recruited to sites of infection inflammatory signals
What do basophils and eosinophils do (3)
Release chemicals such as histamine, heparin and cytokines producing acute inflammation
Defence system against large pathogens that cannot be phagocytosed e.g. parasitic worms
key role in mediating allergic responses
Are NK cells part of the innate or adaptive immune system
What are NK cells
Large granular lymphocytes
What can NK cells do?
Kill tumour cells and virally infected cells, can also kill antibody-bound cells and pathogens
Where are B and T cells found?
Constantly circulating through the blood, lymph and secondary lymphoid tissues
When are t and b cells activated
When they meet a pathogen/ antigen
What are B cells responsible for
The production and secretion of antibodies to defend against extracellular pathogens
What type of pathogens do T cells defend against?
Intracellular pathogens (viruses, mycobacterium)
Types of T cells and role
Helper T cells (key immune system regulators)
Cytotoxic T cells (kill virally infected body cells)
What is immunological memory
Once the adaptive immune system has recognised and responded to a specific antigen, it exhibits life-long immunity to this antigen (mediated by memory T cells and B cells)
Innate immune system?
Rapid (mins-hrs), general response to many different pathogens
Adaptive immune system
slow (days), unique response to each individual pathogen mediated by T and B lymphocytes and responsible for generating immunological memory
What is primary lymphoid tissues?
Sites of leukocyte development
What are secondary lymphoid tissues?
Sites where adaptive immune responses are initiated (contain T cells, B cells and dendritic cells
What is the lymphatic system?
System of vessels draining fluid from body tissues - lymph nodes are positioned regularly along lymph vessels (trap pathogens and antigens in lymph)
What is lymphoedema?
Condition of localised fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then the bloodstrem