Imm2011- Cell migration wk 2

During an infection, which two cytokines have been described to also acting on the hypothalamus to promote fever?

TNF and IL-1

At the site of inflammation, where are the chemokines located that can be recognised by circulating leukocytes?

Chemokines are bound to proteoglycans on endothelial cells to be detected by chemokine receptors

What is the name given to the subset or group of cytokines that are responsible for leukocyte migration from blood into tissues, and within tissues to the site of inflammation?

Chemokines; this cellular migration is called chemotaxis and part of the name is shared with cytokines

What is the reason for integrin going from a low affinity state to a high affinity state following stimulation of a neutrophil?

Confines (or restricts) the cell to the site of inflammation by binding strongly to integrin ligand, and being triggered by chemokine to then migrate across the endothelial cell layer into the tissues

In the absence of infection, what is the affinity of the integrin on leukocytes when they are in circulation within the blood?

Low-affinity; they usually need to binf strongly when they need to cross the circulation into the tissues

True or False. Different cytokines tend to bind to a shared cytokine receptor.

False. Cytokines will bind to specific receptors. For example, IL-2 binds specifically to the IL-2 receptor

True or false. A specific cytokine may effect different cells in different ways.

True. There are many cytokines that can promote different responses in different cell types.

TNF can promote endothelial cell activation and neutrophil activiation - are they the same ?

No, they are not the same. While both are triggered by TNF and are part of the inflammatory response, they involve different cell types and have different outcomes:
- Endothelial cell activation helps immune cells like neutrophils leave the bloodstream by increasing adhesion molecules, vascular permeability, and chemokine production.

- Neutrophil activation enhances their ability to move toward infection sites, kill pathogens, and survive longer, by boosting their reactive oxygen species, degranulation, and chemotaxis.

During inflammation, the cytokines TNF and IL-1 act on endothelial cells to increase expression of what molecules associated with leukocyte adhesion?

Selectin and integrin-ligand

: For each of following actions of cytokines, give the term that describes the type of action: 1.Acts on same cell that produces it 2.Acts on other nearby cells 3.Acts at distant site

Same=Autocrine; Nearby=Paracrine; Distant=Endocrine

From where is the term chemokine derived?

Chemoattractant cytokine OR from chemo- meaning 'chemical' and -kino meaning 'movement'

How do naive T cells enter the lymph node?

Through the high endothelial venules