5 areas med where immunology important
allergies, autoimmune disorders, transplantation, cancer, infectious disease
3 ways body respond to microbes
tolerance, segregation, combat
fxns of human immune sys:
1) create phys/bio/chem barrier that prevents foreign material enter sterile body sites 2) distinguish self and non self 3) create a memory of prior encountered foreign stuff so later exposure can respond faster and stronger
2 basic mechanisms of immunity:
innate and acquired
non-specific defense, respond same way regardless of microbe type (no memory); involves external barrier and internal cell/bio defenses
innate
specific defense, individual response designed for each diff microbe, has memory; involves Ab-mediated (humoral) immunity and cell-mediated immunity
adaptive (acquired)
what are diff external entry barriers?
structural defenses (skin, mucous membranes),mechanical defenses (urine, tears, saliva), microbial defenses (gut bacteria), and biochem defenses (eg. lysozyme)
how structural defenses work?
dry salty enviro, removal through dead skin cell loss, hard to penetrate
internal cell/bio defenses kick in when ___
pathogen overcomes surface barriers
what are the diff internal cell/bio defenses?
interferon, phagocytosis, inflammation, complement, fever
interferon has anti-____ action
viral
what is interferon?
small peptide produced by virus infected cell, tells other cells to make antivirus; host specific and virus nonspecific
3 diff types INF:
alpha and beta (antiviral), gamma (stim phagocytic cells and helps regulate parts of acquired immune response)
what is phagocytosis?
process which certain cells digest/remove dead tissues and foreign material penetrating external surface barrier
what are phagocytes?
WBC: monocytes/neutrophils/eosinophils (bloodstream), macrophages (monocytes migrated into deeper tissues), dendritic cells (close to body surface)
relative proportion of WBC that helps diagnose disease is called:
WBC differential
bacterial infection often give ___ in total WBC, ___ in neutrophiles, ___ in bands
increase in all
viral infections give ____ total WBC, ___ lymphocytes
decrease; increase
increase in total WBC also due to :
leukemia, trauma, stress
decrease in total WBC also due to:
radiation therapy, bone marrow disease
mech of phagocytosis:
1) bacterium attached to mem evaginations (pseudopodia) 2) ingested, form phagosome 3) fuse with lysosome 4) enzymes digest captured material 5) digestion products released from cell
is phagocytosis specific?
nope
what are pattern recognition receptors
proteins on surface of phagocytes that recognize characteristic cules in microbes and not in host cells
what happens to digestion products?
adsorbed and further degraded, may irritate surrounding tissues when there is lots
how bacteria defend selves?
produce capsular polysacc, secrete toxins that kill phagocytes, escape and grow in the cytoplasm (eg. Listeria)
how to kill parasite?
eosinophils secrete toxic protein perforate parasite wall
how to kill virus?
NK cells recognize virus infected cell and destroy by degradative enzymes
rapid bio response to tissue damage
inflammatory response
classic features inflammation
redness, swelling, heat, pain
inflammation overview
1) tissue injury trigger release of chem signals (ie. histamine) 2) dilation and ^ leakiness of local BV, migration of phagocytes to area 3) phagocytes consume microbes and debris, tissue heals
what does histamine do:
vasodilate (redness, heat), increase leakiness of BV (edema), stim nerve endings (pain)
what does prostaglandin do?
vasodilate, fever, ^ sensitivity to pain, atttract phagocytes and other repairing cules/proteins
aspirin and ibuprofen block synth of:
prostaglandin
use of corticosteroids for inflammation:
multi effects on cells, suppress inflammatory chem
acute inflammation?
immediate/beneficial, resolve <2 wks once cause removed or healed, no long term consequence
chronic inflammation?
delayed, potentially harmful; persistent injury/microbe, or other condition, slow to resolve; tissue damage, scarring
a family of around 30 diff proteins in blood serum, make up 10% total serum protein
complement (complement the action of Ab)
3 fxn of complement?
1) make phagocytosis more efficient via opsonization 2) MAC 3) regulate inflammation/immune response
what is opsonization?
coat bacterial cell surface w/ complement protein, receptors on macrophage recognize complement and swallow efficiently
bio response to external/internal pyrogenic agents
fever
external pyrogen examples:
bacterial LPS, fungal wall comps
internal pyrogen examples:
chem released from phagocytes
pyrogens trigger increased ___ production in the ___
PG; hypothalamus (results in ^ hypothal thermoregulation)
benefits of fever:
inhibit growth of temp-sensitive microbes, reduce availability of nutr. req. by microbes, ^ metabolic activity of phagocytic cells, stim. acute inflammation + INF production