First Aid, Chapter 2 Cells Involved in Immune Responses, Endothelial Cells, Smooth Muscle, Fibroblasts

Question 1

Where are endothelial cells found? What are they derived from?

Answer 1

Endothelial cells are specialized, mesenchymally derived cells related to epithelium; they are found on the inside line of blood vessels throughout the body.

Question 2

What are the functions of endothelial cells?

Answer 2

• Maintains homeostasis via vasodilation and vasoconstriction, coagulation and fibrinolysis, wound healing, inflammation, and immunity. -Mediates adhesion and transmigration of circulating leukocytes via selectins and integrins (Table 2-12).
• Certain chemokines can increase the affinity of integrins for their ligands.
• Endothelial cells in the high endothelial vessels display adhesion molecules and chemokines that are responsible for the homing of naive T cells to the lymph nodes.

Question 3

What types of inflammatory changes cause endothelial damage?

Answer 3

• Activation and deposition of inflammatory cells can lead to endothelial disruption and endothelial death, both locally and systemically.
• Antineutrophil cytoplasmic antibodies (ANCA) can lead to widespread endothelial inflammation.
• Deposition of inflammatory cells (in particular, eosinophils) in lung endothelium correlates with airway hyperresponsiveness in asthma.

Question 4

Where is E-selectin located? What is the ligand? Where is the ligand location?

Answer 4

Location: endothelium
Ligand: Sialyl-Lewis X
Ligand location: Leukocytes

Question 5

Where is P-selectin located? What is the ligand? Where is the ligand location?

Answer 5

Location: endothelium
Ligand: Sialyl-Lewis X
Ligand location: Leukocytes

Question 6

Where is L-selectin located? What is the ligand? Where is the ligand location?

Answer 6

Location: Leukocytes (not endothelium)
Ligand: Sialyl-Lewis X on GlyCAM-1 (glycosylation-dependent adhesion molecule)/MadCAM-1 (mucosal addressin cell adhesion molecule)
Ligand Location: High endothelial venules

Question 7

Where are integrins located? What is the ligand? Where is the ligand location?

Answer 7

Location: endothelium
Ligand: ICAM and VCAM
Ligand location: endothelium

Question 8

What is the mnemonic for p selectin?

Answer 8

“P” selectin: think “P”reformed (actually named after platelets)

Question 9

Which selectin is not found on endothelium?

Answer 9

L-selectin (this is found on leukocytes. E-selectin and P-selectin are found on endothelium)

Question 10

What surface markers on the high endothelial venules and naive T cells are responsible for homing to the lymph nodes?

Answer 10

CCL19 and CCL21 by the high endothelial venule, and CCR7 on the naive T cell

Question 11

What integrin ligands are found on the surface of activated endothelium?

Answer 11

ICAM-1, ICAM-2, VCAM-1

Question 12

Describe smooth muscle. Where is it found? What is an antibody found against it? What disease is that found in?

Answer 12

Smooth muscle is an involuntary, nonstriated muscle found in vessels walls. An IgG autoantibody (anti-SMA) is directed against smooth muscle in type I autoimmune hepatitis.

Question 13

What do fibroblasts make? What do they secrete and what cell is that important for? What is an important role of fibroblasts?

Answer 13

Fibroblasts are a type of cell that makes collagen and other components of the extracellular matrix. Fibroblasts secrete growth factors, including stem cell factor, which is essential for mast cell differentiation and survival. Fibroblasts are particularly important in wound healing