11. White Blood Cells + Innate imm system Flashcards
name the 3 granulocytes
Neutrophils
Eosinophils
Basophils
name the 3 lymphocytes
B Lymphocytes
T Lymphocytes
Natural killer cell
which WBC in its own catgory
monocyte
why are large orgnaisms e.g. worms tricky to kill
- cannot be engulfed and digested
- has a protective sheath that neutrohphils find it hard to get through
why are bacteria hard to kill
needs to be killed or AT LEAST sequestered quick and effective before they can replicate/cause damage
why are viruses tricky to kill
hidden from immune system inside normal cells
why tetanus called lockjaw
bacteria produces a toxin that enters CNS
which causes mucles to spasm
can eventually cause breathing problems
what cell is responsible for getting rid of toxins or small blood pathogens
B lymphocytes
covid 19: something to detect vcovid 19 exposure
detecting neutralising antibodies
covid 19: something other than neutralising antibodies that may be important in long term protection
t-cell resposne
cells of the INNATE immune system
neutrophils
eosinophils
basophils
monocytes
2 mechanisms of recognition of pathogen
PAMPS – pathogen associated molecular pattern
DAMPS (cell walls etc) – damage associated molecular patterns (released DNA etc)
4 main steps of pathogen recognition and response
- increased production of appropriate white cells
- recruitment of white cells to correct place
3 . activation of white cells to improve function - control to limit self harm from white cell response
how might productioin of appropriate white cells be increased
cytokines acting on haematopoiesis
e.g. G-CSF = more neutrophil
GM-CSF
M-CSF
how do white cells get recruited to the correct place
response caused by DAMPS and PAMPS = release of chemokines
which signal other wbcs to come
example of chemokines
interleukin 8
attracts neutrophils
(diff ones attract diff cells duh)
what allows white cells to be activated
cytokines and chemokines
‘prime’ the cells
example of how G-CSF primes neutrophils
increases adhesion, granulation (=hypergranular), responsiveness
what would limit the WBC response
was the cause of infection (whatever pathogen) is killed, DAMPS and PAMPS decrease
= the first 3 steps decrease
which cells kill bacteria
neutrophils and monocytes
how long do neutrophils survive
12-24 hrs in blood
24-48hrs in tissues
(most die wihtout doing anything cuz never get stimulated)
what is released in infection that enhances neutrophil function
cytokines and chemokines
how do neutrophils adhere to bacteria
using adhesion receptors
what types of granules fuse with phagosome to destroy bacteria
- microbiocidal = myeloperoxidase, lysozymes
- acid hydrolases
- iron binding
what is extracellular trap that can be used to immobilise bacteria
DNA net
3 ways neutrophils prevent tissue damage
- phagocytosis = destroys internally
- enzymes contents work best at low pH, so dont do much outside the cell
- neutrophils apoptose after it kills cells
when do monocytes turn up
- continue effects of neutrophil at later stage
monocytes life span
17hr in blood
then enter tissues where they can survive a few weeks
3 functions of monocytes
- pahgocytose bacteria
- form granuloma = “wall in” pathogens
- remove dead cells and promote wound healing
name a disease that macrophages act on
TB
the bacteria can survive here for extended periods
which 2 cells are responsible for killing larger organisms
eosinophils (red) and basophils (blue)
(functionally basically the same)
difference in staining
= do this by releasing granules into tissues
eosinophil granules: histamine
- dilate blood vessels
- causes swelling to trap invading organism
eosinophil granules: active proteins
- nucleases
- lipases
= these are relatively non toxic to our tissues
and swelling means they dont migrate too far
what granules do basophils have
- histamine
- serotonin
= these 2 dilate blood vessels - heparin
= prevents clotting - enzymes = break down tissue matrix = easier for immune cells to get in
- IL4 = stimulates immune reactions
what chediak-hihashi syndrome
abnromal granules in neutrophils
what is autoimmune neutropenia
Too few neutrophils = immune system attacks neutrophils = less in blood
how might someone get too many neutrophils
e.g. during chemotherapy recovery, may need to inject with GS-CSF
and this can cause too many to be produced
what is a disease caused by too many neutrophils
rheumatoid arthiritis
key symptom of rheumatoid arthiritis
ulnar drift
rheumatoid arthiritis treatment
immunosuppresants
e.g. methotrexate
how can eosinophils cause disease
Eosinophils can release their granules quite easily
e.g. when travelling through heart valves, can encounter trauma by valves,
See this as a threat and release their granules
= damage to heart valves
basophils disease
main one is asthma:
Hyperactive basophils = can trigger asthma = too many histamines and serotonin released = swelling of airways
what is cytokine storm
cytokines and chemokines cause excessive activaiton of inflammatory cells = destroy normal tissues = these release more cytokines = uncontrolled inflammation
cytokine storm in covid 19
B and T lymphocytes which usually respond to viral infection become uncontrolled =
inappropriate activation of innate immune system =
increasing cytokine release =
multi organ damage
what can be used to prevent cytokine storm
dexamethosone (steroids)
must be used at early stage
