Lecture 21: Regional and System Specific Immunology Flashcards Preview

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Flashcards in Lecture 21: Regional and System Specific Immunology Deck (23)
1

What do osteoclasts differentiate from?

myeloid progenitors (monocytes)

2

What are the 2 fates of monocytes?

macrophages and osteoclasts

3

What 2 factors are ESSENTIAL for differentiation and maturation of macrophage/monocyte precursors into osteoclasts?

M-CSF and RANKL

4

What can bind and neutralize RANKL (thereby negatively regulating osteoclastogenesis)?

OPG

5

How do OBs, OCs, and immune cells communicate with each other?

RANK-RANKL system

6

What cells release M-CSF?

Osteoblasts

7

The ratio of _____ and ______ determines bone formation

OPG and RANKL

8

True or false: any condition that promotes OC dominance will be associated with bone pathology

true

9

What turns cells on?

RANKL (then osteoblasts can secrete M-CSF)

10

What effect does M-CSF have?

turns on pre-osteoblasts (to increase #)

11

Aside from osteoblasts, what else can secrete RANKL?

B and T lymphocytes

12

True or False: RANKL is expressed only by monocytes

FALSE - also neuts, DC, T and B cells

basically, they can all activate osteoclasts

13

Which cytokines promote osteoclasts and how do they do it?

IL-1, 6, 8, 17, and TNF
(the proinflammatory cytokines)

they induce RANKL (OPG cannot keep up)

14

Which cytokines inhibit OC?

4 and 10 (anti inflammatory ones)

15

What effect does Th1 response around bone have?

pro-clastogenic and bone resorption

OC activation

16

What effect does Th17 have on bone?

POTENT OC activator

on the flip side, a normal Th1 or 2 response wouldn't be such a bad thing since it can block this

17

Which is more damaging to bone, Th1 or Th17?

Th17

18

What is a clinical example of unbalanced bone remodeling?

rheumatoid arthritis

19

What cytokine is elevated in the synovium of the joint in RA patients?

IL-23

20

Which cytokine of a Th17 response activates neighboring OC to proliferate?

IL-17

21

If B and T cells are the source of RANKL, how can RA be treated?

lots of monoclonal antibodies!

22

Why is bone loss a common problem in post menopausal women?

estrogen is a stimulator of OPG (blocks RANKL so OC isn't stimulated)

23

What is a drug you can give to post menopausal women to prevent OC?

denosumab (an anti RANKL monoclonal)