abbas chapter 2

Question 1

phagocytes

Answer 1

neutrophils are most abundant - production of them increases with infection
monocytes also
blood cells recruited to site of infection - ingest tiniest microbes for intracellular killing

Question 2

healthy neutrophil count

Answer 2

4000-10000/mm^3
with infection can get up to 20000
production stimulated by cytokines

Question 3

neutrophils

Answer 3

ingest macrophages etc in blood and enter tissue and ingest more microbes
die within a few hours
migrate by binding endothelial adhesion molecules and in response to chemoattractants that are produced on encounter with microbes

Question 4

healthy monocyte count

Answer 4

500-1000 mm^3

Question 5

monocytes

Answer 5

migrate by binding endothelial adhesion molecules and in response to chemoattractants that are produced on encounter with microbes - macrophages in tissue release cytokines
also ingest microbes in blood and tissues but differentiate into macrophages in tissue

Question 6

TNF and IL1

Answer 6

act on endothelium of small vessels at site of infection

released by macrophages

Question 7

E and P selectin and phagocytes binding to endo cells

Answer 7

adhesion molecules expressed by endo cells
neutrophils and macrophages have surface carbs that loosely bind to these
blood causes them to roll => repeated bindings
chemokines expressed on endo cells cause phagocytes to increase integrin expression => eventually in firm binding

Question 8

chemokines

Answer 8

released by endo cells to increase phagocyte binding and by macrophages
stimulate motility - encourage phagocytes to migrate into extravascular space

Question 9

inflammation

Answer 9

caused by accumulation of leukocytes, vascular dilation, and increased vascular permeability

Question 10

toll-like receptors

Answer 10

specific for different composition of microbes

when engaged => activation of transcription factor NF-kappaB

Question 11

actions of macrophages and neutrophils

Answer 11

phagocytose microbes

recruit more macrophages and lymphocytes => granulomas

Question 12

granulomas

Answer 12

collections of cells around microbes

Question 13

macrophages

Answer 13

can also release cytokines, GF and enzymes that remodel injured tissue and replace it with connective tissue
stimulate T-lymphocytes

Question 14

natural killer cells

Answer 14

lymphocytes that repond to intracellular microbes by killing infected cella dn by producing the macrophage-activating cytokine IFN-8
recognize host cells that have been altered by microbial infection
when activated, release proteins from granules toward infected cells = molecules create holes in plasma membrane and other proteins that enter cells and induce apoptosis
also synthesize and secrete cytokines IFN-gamma

Question 15

NK cell receptors

Answer 15

Killer cell Ig-like receptors (KIRs)
CD94 protein/lectin subunit NKG2
both have cytoplasmic domains with immunoreceptor tyrosine based inhibitory motifs (ITIMs)
phos on tyrosine residues when bind class I MHC
binding promotes activation of cytoplasmic protein tyrosine phosphatases - remove phos from secondary molecules => inhibits NK activity => keeps NK cells shut off when encounter self NK cells

Question 16

IFN-gamma

Answer 16

cytokine released by NK cells

activates macrophages

Question 17

IL-12

Answer 17

released by macrophages when stimulated by IFN-gamma

activates NK cells to secrete more IFN-gamma

Question 18

alternative pathway

Answer 18

when complement proteins activated on microbial surfaces and cannot be controlled because complement regulatory proteins not present on microbes (innate)

Question 19

classical pathway

Answer 19

triggered after antibodies bind to microbes or other antigens (humoral)

Question 20

lectin pathway

Answer 20

when the plasma protein mannose-binding lectin binds to terminal mannose residues on surface glycoprotein of microbes => activation of proteins of classical pathway

Question 21

complement activation

Answer 21

when activated, C3 cleaved to C3b and C3a
breakdown products of complement proteins attract neutrophils, monocytes, promote inflammation
activation also results in formation of protein complex that makes pores in microbial cell membrane

Question 22

C3b

Answer 22

covalently attaches to microbes - activates downstream complement proteins on microbial surface
coats microbes and promotes phagocyte binding

Question 23

cytokines

Answer 23

soluble proteins that mediate immune and inflammatory responses
communication between lymphocytes and each other and other cells
most in innate immunity produced by macrophages
in cell-mediated immunity can be produced by T lymphocytes
can be paracrine or autocrine
circulating levels increase after infection

Question 24

TNF

Answer 24

cytokine

causes septic shock when overproduced by macrophages responding to bacterial LPS => decreased BP

Question 25

plasma-mannose-binding lectin (MBL)

Answer 25

recognizes microbial carbs and coats microbes for phagocytosis or activates compliment via lectin pathway

Question 26

c-reactive protein (CRP)

Answer 26

binds on microbes and coats them for phagocytosis by macrophages (macrophages have CRP receptor)

Question 27

signals produced by dendritic cells and macrophages

Answer 27

both types activate T lymphocytes
costimulators - surface molecules that bind to naive T cells - activate
secrete IL-12 - stimulates diff. of naive T cells into effector cells

Question 28

C3d

Answer 28

B cells recognize it on microbes - this and antigen differentiation => b cell differentiation