IIH L08 Sepsis and the acute inflammatory response

Question 1

Where are dendritic cells found? L08

Answer 1

All tissues

Question 2

Where do dendritic cells migrate to when activated by local tissue injury? L08

Answer 2

Secondary lymphoid organs (thymus or spleen)

Question 3

What are dendritic cells known as when migrating? L08

Answer 3

Interdigitating

Question 4

What are the three functions of DCs? L08

Answer 4

Pick up and process antigen, migration to T-cell rich areas, and transmitting danger signals through Toll-like receptors

Question 5

What are Follicular DCs? L08

Answer 5

They present native antigen to B cells

Question 6

What is the name of DCs that are in the tissue and have not taken up antigen yet? L08

Answer 6

Langerhans cells

Question 7

When the peptide has been phagocytosed and taken up into the peptide binding grooves of MHC II, what is the name of the co-stimulatory molecules that are transported with the peptide to the cell surface? L08

Answer 7

E.g. CD40 or CD86

Question 8

What are Peyer’s patches? L08

Answer 8

Aggregations of lymphoid tissue in the ileum of the small intestine

Question 9

What do monocytes become in tissues? L08

Answer 9

Macrophages

Question 10

Where are fixed beds of macrophages? L08

Answer 10

Liver and spleen; they are perfused by blood sinusoid

Question 11

What are Kupffer cells? L08

Answer 11

Liver macrophages; perfused by portal blood supply

Question 12

Where are the macrophages in the spleen? L08

Answer 12

Red pulp

Question 13

When mast cells degranulate, what do they release? L08

Answer 13

Histamine, tryptase, kallikrein, and heparin

Question 14

What inhibits NK cells? L08

Answer 14

Expression of MHC on the antigen; otherwise it instinctively kills the cell

Question 15

Which cells are particularly killed by NK cells? L08

Answer 15

Virus-infected or tumour cells as they often do not express MHCs

Question 16

What do neutrophils do if they are overwhelmed? L08

Answer 16

Form nets of fibrous bands and release their DNA material and toxic substances to trap bacteria

Question 17

What substance inhibits neutrophil granules from damaging host cells? L08

Answer 17

alpha-1 anti-trypsin

Question 18

What is an anti-inflammatory cytokine? L08

Answer 18

IL-10

Question 19

What is a ‘stop’ cytokine? L08

Answer 19

fMLP

Question 20

How long do neutrophils circulate in the blood in the absence of infection? L08

Answer 20

12-16 hours

Question 21

What are possible causes of neutropenia? L08

Answer 21

Aplastic anaemia, cancer, radiation, B12 deficiency, chemotherapy, and autoimmune neutropenia

Question 22

What do active neutrophils stimulate? L08

Answer 22

Chemotaxis, degranulation, and superoxide release

Question 23

What causes alpha-1 anti-trypsin deficiency? L08

Answer 23

Liver disease or lung damage

Question 24

What happens in Chronic Granulomatous Disease? L08

Answer 24

Failure of NADPH oxidase complex formation so superoxides are not released, resulting in severe and recurrent infections

Question 25

What stimulates mast cell degranulation in the acute inflammatory response? L08

Answer 25

C3a

Question 26

What binds to the bacterial cell wall causing it to release histamine in the acute inflammatory response? L08

Answer 26

C3b

Question 27

What does C5a do in the acute inflammatory response? L08

Answer 27

Increases vascular permeability and chemotaxis for neutrophils by increasing expression of adhesion molecules on the endothelium

Question 28

What interleukin induces chemotaxis? L08

Answer 28

IL-8

Question 29

What are examples of the many inflammatory cytokines that activate the endothelium to express adhesion molecules? L08

Answer 29

Histamine, prostaglandins, leukotrienes, IL-8, IL-1, IL-6, TNFalpha

Question 30

What is step one of trans-endothelial migration of neutrophils? L08

Answer 30

Rolling and tethering

Question 31

What do neutrophils bind to on the endothelium in step one of trans-endothelial migration? L08

Answer 31

Selectins

Question 32

What is step two of trans-endothelial migration of neutrophils? L08

Answer 32

Chemokine receptors bind to chemokines on luminal side of endothelium; this promotes neutrophil integrin activation

Question 33

What is step three of trans-endothelial migration of neutrophils? L08

Answer 33

Activated integrins on neutrophils bind to their ligands using intracellular adhesion molecules (ICAMs) expressed on endothelium

Question 34

What is step four of trans-endothelial migration of neutrophils? L08

Answer 34

Once within the tissue the neutrophil can further respond to chemokine gradients for correct positioning within the cell

Question 35

What is the receptor for C3b? L08

Answer 35

CR1

Question 36

What is the receptor for iC3b? L08

Answer 36

CR3/4

Question 37

What receptors do neutrophils use during a primary infection? L08

Answer 37

Complement receptors

Question 38

What receptors do neutrophils use during a secondary infection? L08

Answer 38

Complement and Fc receptors

Question 39

Following phagocytosis, what products do neutrophils and macrophages release to help kill engulfed microorganisms? L08

Answer 39

Reactive oxygen species (O2-), hydrogen peroxide (H2O2), and nitric oxide (NO)

Question 40

What happens if the number of apoptotic neutrophils overwhelms the number of macrophages needed to clear them? L08

Answer 40

The neutrophils die by secondary necrosis releasing their toxic contents leading to pus and abscess formation

Question 41

When does sepsis occur? L08

Answer 41

When an infection spreads from tissue to the blood, then a systemic inflammatory response

Question 42

What is an example of excessive mast cell degranulation? L08

Answer 42

Asthma, hay fever

Question 43

Which cells proliferate to produce new vasculature? L08

Answer 43

Fibroblasts lay down collagen

Question 44

What is the 'respiratory burst' in neutrophils? L08

Answer 44

Production of superoxide ions increases oxygen consumption