immunology Flashcards
variolation
exposure of an individual too the contents of dried smallpox pustules from an infected patient
how can new infectious disease emerge ?
global village
population growth
changes in human behaviour
changes in dynamics of other infections
loss of natural habitat
interactions of pathogens with humans
what are barriers to infection
skin - physical barrier, physiological factor, sebaceous glands
mucous
commensal bacteria
what gives optimal effectiveness ?
a balanced immune system
what are the two different immune systems ?
innate immune system
adaptive immune system
immune over reactions
reaction to ‘self’ - autoimmunity
reaction to inn
immune under reactions
how can we prevent or treat human health
we can manipulate the immune system by:
immunisation
anti-inflammatory and immunosupprisive drugs
cancer immunotherapy
what does the innate immune system responsible for?
rapid responce (0-4 hours)
general response
responsible for acute inflammation and killing of pathogen
what is the adaptive immune system responsible for ?
slow response (4-96 hours)
unique response
what cells do innate immune systems involve ?
mast cells
NK cells
phagocytes
complement
PAMPs:PRRs
what cells does the immune system contain ?
phagocytes
lymphocytes
eosinophils, mast cells and basophils
what are examples of phagocytes ?
neutrophils
monocytes
macrophages
dendritic cells
what do phagocytes do ?
ingest and kill bacteria
whats an important source of cytokines ?
phagocytes
what are examples of lymphocytes ?
T cell
B cells
NK cells
What are examples of eosinophils, mast cells and basophils ?
Granular cells
what do eosinophils, mast cells and basophils do ?
release chemicals for acute inflammation
what are examples of soluble (humoral factors) ?
antibodies
complement proteins
what are immunoglobulins ?
antibodies
when are antibodies produced ?
in response to an antigen
what role do complement proteins have ?
critical role in inflammation and defence
where do mast cells reside ?
in tissue
what do mast cells protect ?
mucosal surfaces
what do mast cells degranulate and release ?
histamine and tryptase
what are mast cells involved in ?
give examples
gene expression - TNF, chemokines, leukotrienes
where can you find basophils and eosinophils ?
circulate in blood
what do basophils and eosinophils do ?
recruited to sites of infection
where can you find neutrophils ?
they circulate freely in blood
When are neutrophils needed ?
rapidly recruited to inflamed and infected tissues
what are neutrophils ?
short-lived professional killer cells
how do neutrophils involve ?
PAMP recognition and activation
how do neutrophils attack pathogens ?
phagocytosis
release of antimicrobial peptides and degradative proteases
generate extracellular traps
what do neutrophils produce ?
activate neutrophils and produce TNF
what is PUS
dead and dying neutrophils + tissue cells + microbial debris = PUS
what are monocytes ?
precursors of macrophages
what is the main purpose of monocytes and macrophages ?
limit inflammation
involved in tissue repair and wound healing
where are macrophages located ?
reside in tissues
what do macrophages do ?
ingest and kill extracellular pathogens
kill debris from dead tissue cells
inflammation
tissue repair and wound healing
antigen presentation
what are dendritic cells ?
immature cells in peripheral tissue
what do dendritic cells do ?
stimulate adaptive immune responses (antigen presentation ?
when do mature dendritic cells occur and what happens ?
when in contact with pathogen, mature dendritic cells migrate to secondary lymphoid tissues
what are natural killer cells (NK) ?
large granular lymphocytes
what do natural killer cells (NK) do ?
specifically kill tumour and virally infected cells
can also kill antibody-bound cells
what are T cells and B cells ?
mature cells that constantly circulate through blood, lymph and secondary lymphoid tissues
what do B cells do ?
produce antibodies
What do T cells do ?
defence against pathogens
What are helper T cells ?
regulators of immune system
what do helper T cells do ?
activate other immune cells
what are the different types of T cells ?
Helper T cells
Cytotoxic T cells
How do T cells work ?
steps example
CD8 + produce cytokines
regulates other white blood cells
activates CD8 and B cells
peptides on HLA class II molecules
What do cytotoxic T cells do ?
kill virally infected body cells
How do cytotoxic T cells fight ?
steps example
CD8 (which are cytotoxic) recognise peptides in association with HLA class I
trigger apoptosis
secrete cytokines and pore-forming molecules like perforin
what is the fate of B cells and T cells ?
effector cells or memory cells
where is the site of leukocyte development ?
primary lymphoid tissue
what is the secondary lymphoid tissue ?
sites where adaptive immune responses initiated
What are the mechanisms of communication in the immune system ?
direct contact - ligand interactions
indirect - production and secretion of cytokines
why are cytokines produced ?
in response to infection, inflammation and tissue damage
how do cytokines work ?
co-ordinate the immune system by modulating cell behaviour
what are examples (and their functions) of cytokines ?
interferons - anti-vira functions
TNF (tumour necrosis factor) - pro-inflammatory
chemokines - control and direct cell migration
interleukins - various function,IL2 (T cell proliferation)
IL10 (anti-inflammatory)
what are local effects of acute inflammation ?
redness, heat
swelling
pain
loss of function
what are systemic effects of acute inflammation ?
fever
what are the phases of innate immune response ?
recognition phase
activation phase
effector phase
what receptors are involved in recognition phase ?
PRRs
PAMPs
