26/03

Question 1

Differences between DAMPs and PAMPs

Answer 1

DAMPs: damage associated molecular patterns, series of molecules released by dying cells
PAMPs: pathogen associated molecular patterns, unspecific molecules present on the surface of pathogens

Question 2

Which mediators can we find inside the granules of basophils and mast cells? (according to the timing of the production)

Answer 2

• Pre-formed mediators constitutively present: histamine, serotonin, proteases, TNF-α… They’re immediately released after the recognition of alarm signals
• Synthesized after few minutes after the degranulation of the first granules: thromboxane, prostaglandins, leukotrienes. They have to recruit neutrophils in the area
• Synthetized hours after activation: cytokines and chemokines. They recruit the proper cells needed to fight against the pathogen. They’re called “latter mediators” because they need the transcription of new genes

Question 3

Which receptor recognize DAMPs and PAMPs? On which cells it’s present

Answer 3

PRM: pattern recognition molecules.
Soluble or expressed by innate leukocytes, macrophages or dendritic cells

Question 4

Which are the components of the innate response?

Answer 4

anatomical barriers
physiological barriers: pH, enzymes
PRM
Complement
Inflammation
Phagocytosis and target cell lysis: mediated by innate cells

Question 5

Which are the characteristic molecules with anti-bacterial activity (chemical barriers)?

Answer 5

• peptides: lysozymes, beta defensin, cathelicidin, , pentraxin
• alarmins
• cytokines
• chemokines

Question 6

What’s the role of lysozyme? Where can we find it?

Answer 6

It can break the 1-4 glycosidic bond connecting N-acetylmuramic acid and N-acetylglucosamine. It destroy expecially GRAM+ walls.
It’s produced by salivary glands, paneth cells, granulocytes

Question 7

Structure and role of cathelicidin

Answer 7

small anti-microbial peptide always present as precursor. When cleaved they can destroy the lipoproteic membrane of bacteria

Question 8

Pentraxin: structure and role

Answer 8

cyclic pentameric molecule that binds to the surface of microbes. They’re considered PRM

Question 9

Which different kind of mucosae we can have?

Answer 9

mucosa of the lips and the mouth
bronchial
digestive
rectal

Question 10

immune cells: percentages of presence in the blood

Answer 10

basophils: 0-1,5
neutrophils: 40-74
eosinophils: 0-7
monocytes: 3,4-9
lymphocytes: 19-48

Question 11

Examples of DAMPs and PAMPs

Answer 11

DAMPs: heat-shock proteins, altered membrane phospholipids, complement products
PAMPs: nucleic acids, surface glycoproteins, membrane components

Question 12

Which are the function of neutrophils?

Answer 12

Sentinel activity
Phagocytosis
Spiderman effect: DNA net to capture the bacteria
Kamikaze effect

Question 13

Which are the most important functions of eosinophils?

Answer 13

anti-helminthic activity, anti-tumor activity, phagocytosis

Question 14

What are monocytes and in what can they differentiate?

Answer 14

They’re small cells with a V-shaped nucleus and no granules.
They can differentiate in tissues’ macrophages or dendritic cells

Question 15

Which type of dendric cells can we have?

Answer 15

• Conventional dendritic cells (immature): they’re able to phagocyte
  o Conventional (es: resident cells like Langerhans)
  o Plasmacytoid: produces interferon
• Mature dendritic cells: they’re the professional antigen presenting cells

Question 16

Which ligands can activate a NK cell?

Answer 16

Hemagglutinin
Stress ligand (MICA, MICB)
HLA or MHC molecules

Question 17

Which cytokines are released by NK cells?

Answer 17

• IL2: increase lytic activity and degranulation of NK cells
• IL4: decrease lytic activity of NK cells
• IL15: important for maintenance and proliferation of NK cells
• GM-CSF: induce the bone marrow to produce neutrophils, eosinophils and monocytes
• INF-γ: it’s active on T cells and macrophages

Question 18

How did we get the information on hematopoies and the cell that are formed?

Answer 18

All the information about these cells and progenitors were made thanks to single cell transcriptomic analysis. We discovered that they mature differently because of different patterns of transcription in the nucleus or in the cytosol (epigenetic memory).