C. 2nd Line of Defense of Innate Immunity Phagocytes

Question 1

neutrophils

Answer 1

circulate in blood and extravasate in response to infection. they are 1st phagocyte to arrive in tissues where they die a few days after

Question 2

macrohpahes

Answer 2

monocytes circulate in blood and then extravasate where they are signaled to become macrophages. some tissues have resident macrophages. live longer than neutrophils and have other roles in immune system

Question 3

name a resident macrophage

Answer 3

aleveolar macrophage are found in lungs

Question 4

phagocytosis steps

Answer 4

extravastion, attachment, engulfment, killing/digestion, and production of ROS and RNS

Question 5

extravastion

Answer 5

neutrophils extravasate first followed a few hrs later by monocytes/macrophages

Question 6

attachment

Answer 6

once phagocyte has reached site of infection, next step is to adhere to bacteria. does so by its diff TLR

Question 7

toll like receptors TLR fn

Answer 7

bind to peptidolgycan on gram +ive bacteria, anoter one binds to LPS of gram -ive, and anoter binds to flagellin

Question 8

how can binding of TLR be enhanced

Answer 8

if bacteria surface is coated with an opsonin like the complement C3b. phagocytes have C3bR

Question 9

engulfment

Answer 9

PM of phagocyte used recpetors to bind like a zipper around bacterium. bacterium is taken up into a endosome called phagosome. protons are pumped into phagosome cause pH to decrease

Question 10

killing/ digestion

Answer 10

a phagolysosome is formed by fusion of phagosome with lysosomes. enzymes used to produce reactive O2/nitrogen species (ROS and RNS) are activated

Question 11

lysosomes contains

Answer 11

cationic peptides, lysozyme, lactoferrin and degradative enzymes

Question 12

production of ROS and RNS needs

Answer 12

the phagocytes to undergo respiratory burst. meaning uptake and use of O2 increases

Question 13

to produce ROS

Answer 13

an NADPH oxidase used NADPH to reduce O2 prodcuing supoeroxide anion O2-. superoxide anion is converted to H@)@ by superoxide dismutase. other enzymes convert H2)2 to other ROS including hypochlorite ions OCl-

Question 14

to produce RNS like nitric acid we need

Answer 14

O2, an aa and NADPH are used

Question 15

fn of ROS and RNS

Answer 15

oxidize bacterial components which kills bacterial cells. bacterial molecules will be digested and recycled