Immuno lec 8 Flashcards
What is cystic fibrosis?
A disease where mucous is extremely thick due to lack of water, so mucous can’t be removed by ciliary action, causing bacterial growth.
What are antimicrobial peptides?
Also called host defense peptides.
Part of the innate immune system found among all life classes.
What are defensins?
Small cationic peptides produced by epithelial cells and by neutrophils, NK cells, and killer T-cells.
produced by neutrophils and various barrier epithelia, after cleavage they have bactericidal and immunomodulatory functions
Cathelicidins
Why is it important that defense peptides are positively charged?
To be attracted to negatively charged bacterial membranes, thereby destroying them.
What is primary ciliary dyskinesia?
inherited disorder that leads to impaired mucociliary clearance, and repeated chest infections
Why are eczema patients at higher risk of getting infected?
The outer layer of the skin is always cracked, creating entry points for pathogens.
What are intraepithelial T-cells?
T-cells lacking CD4 and CD8 and are found in the epithelium. They respond to pathogens but have limited diversity, in addition to not being able to recognize MHC 1. They have a gamma-delta receptor that may detect peptides and non-peptide antigens.
What is inflammation?
The recruitment of leukocytes and plasma proteins from the blood to sites of infection and tissue injury, it also results in endothelial cell activation.
How do circulating leukocytes reach the site of injury?
They move closer to the venule wall, then attach to selectins then to integrins with specific receptors, then the leukocyte enters by paracellular transmigration between the endothelial cells, following chemokines.
What are selectins and when are they displayed?
Selectins are plasma membrane carbohydrate-binding adhesion molecules that mediate an initial step of low affinity adhesion of circulating leukocytes to endothelial cells.
They are displayed in response to IL-1 and TNF.
What are integrins and when are they activated?
Heterodimeric cell surface protein that helps in adhesion of cells to other cells or ECM.
They exist in a low-affinity state and turn into the high-affinity state in response to intracellular signaling and chemokine reception.
What is ICAM-1?
A ligand for leukocyte function associated antigen 1 (LFA-1) (an integrin).
What are the 2 major families of chemokines, where are they produced, and what is their receptor?
CC and CXC chemokines (cysteine-cysteine and cysteine-amino acid-cysteine).
Produced by leukocytes, endothelial and epithelial cells.
Bind to GPCR.
Chemotactic.
What is IL-8 and its functions.
A chemokine of CXC family, that is released by macrophages, epithelial cells, and endothelial cells.
Chemotactic agent for neutrophils and inducive to phagocytosis.
It is sometimes released by cancer cells to increase angiogenesis later on.
