lecture 3

Question 1

neutrophils

Answer 1

most abundant phagocyte produced in bone marrow
first cells attracted to site of inflammation
cytokines/chemokines stimulate neutrophil migration from the blood into the infected/damaged tissue
capture, phagocytose and kill microbes (oxidants, defensis, lytic enzymes)
opsonized microbes are more efficiently ingested and killed
short lived; unable to undertake prolonged/multiple phagocytosis - chemicals within damage them

Question 2

how many neutrophils are made per day

Answer 2

10^11 in adult humans! 1800-7700 in blood cell counts

Question 3

opsonins

Answer 3

antibodies and complement proteins

Question 4

neutrophil properties

Answer 4

major blood leukocyte to repsond to injury
60-75% of leukocyte population in carnivores
20-50% ‘’ in horses and ruminants
migrate to tissues within 12 hours
live for 24 - few days
primary and secondary granules (effector molecules)
segmented nuclei

Question 5

generation of neutrophils

Answer 5

bone marrow -> myeloblast -> n. myelocyte -> n. band cell -> mature neutrophil
G-CSF (granulocyte colony stimulating factor) helps

Question 6

location of neutrophils

Answer 6

blood: marginating pool - rolling on epithelial surface and sticky connection between the two slows them down)

circulating pool - circulates throughout blood in blood vessel

Question 7

chemotactic factors

Answer 7

1. chemokines: IL8 (CXCL8)
2. vasoactive lipids: leukotriene B4 (LTB4)
3. complement proteins: C3a & C5a

attract neutrophil into tissue

Question 8

tissues adhere to microbes via

Answer 8

PRR on neutrophils (TLRs)

opsonins: complement of antibody proteins

Question 9

neutrophil response to tissue damage/infection

Answer 9

1. migrate into tissue by chemotaxis
2. once in tissues adhere to microbes
3. phagocytosis of microbes
4. destroy microbes by oxidative and non oxidative mechanisms

Question 10

adhesive molecule expression

Answer 10

after neutrophil is in tissue the selectins and integrins bind the neutrophil and endothelium together

selectin: weak (L on leukocyte, E/P on endothelial cell)
integrin: strong (CD11, CD18 on leukocyte)

cytokines that are released by sentinel cells will increase the expression of adhesive molecules