Immunology basics Flashcards
Briefly describe what the immune system is.
An integrated system of cells and molecules that defends against disease and reacts against infectious pathogens
Name the two arms of the immune system.
Innate
Adaptive
Which is more specific, innate or adaptive?
Adaptive.
It recognises the specific pathogen and kills it, the innate system just kills any pathogen
Which response is more rapid, innate or adaptive?
Innate
Innate develops over hours, adaptive over days/weeks
Which involves the development of immunity, innate or adaptive?
Adaptive
Resistance is improved by repeat infections in adaptive.
Which cells are involved in innate immunity?
Phagocytes
Natural killer cells
Which cells are involved in adaptive immunity?
B and T lymphocytes
What are the soluble factors (found in bloodstream) involved in the innate immune system?
Interferons / interleukins
Complement system
What are the soluble factors (found in bloodstream) involved in the adaptive immune system?
Antibodies
Describe the difference between the primary and secondary contact with the antigen.
Primary contact activates innate and weak adaptive responses
Secondary contact activates enhanced adaptive responses
What are the external barriers to infection?
Keratinised skin
Antibiotic secretions: tears
Mucous: GU, GI and respiratory tracts
Low pH: stomach acid
Commensals: good bacteria
What are leucocytes?
All white blood cells
What are the two branches of phagocytes?
Neutrophils
Mononuclear phagocytes: monocytes & macrophages
What’s the difference between macrophages and monocytes?
Macrophages: mononuclear phagocytes that live in tissues
Monocytes: mononuclear phagocytes that live in blood stream
Which are the main phagocytes in the bloodstream?
Neutrophils
Which phagocytes live longer?
Mononuclear phagocytes
Which phagocytes are more rapid?
Neutrophils
What is the main role of neutrophils?
Kill pathogens by ingesting them and killing them by releasing toxic contents of their lysosomes, such as H2O2
What is the main role of mononuclear phagocytes?
Kill pathogens by ingesting them
Also, help initiate adaptive responses
How do phagocytes recognise pathogens?
They have pathogen-recognition receptors (PRRs)
These recognise pathogen associated molecular patterns (PAMPs)
What are PRRs?
Pathogen-recognition receptors
Phagocytes have them and use them to recognise pathogens
What are PAMPs?
Pathogen associated molecular patterns
These are on the pathogen and are recognised by phagocytes
Give an example of a PRR and PAMP.
On a phagocyte, toll-like receptor (a PRR) recognises a lipopolysaccharides (a PAMP) found on some pathogens
What are natural killer cells? And what do they do?
Lymphocytes that recognise altered self
They induce apoptosis in virally infected cells and cancer cells
They kill target cells unless they recognise a self protein
