Introduction and Innate Immunity Flashcards
What are mast cells?
Found of the mucus membranes, so often the first to encounter pathogens. Release inflammatory mediators and are involved in large parasites and allergy (many Fc receptors for IgE).
What are the mononuclear phagocytes?
Monocytes -> Macrophages, present antigen to T helper cells and are phagocytic.
Name three types of cytokines.
Interleukins (IL1-38), interferons, and chemokines.
What is the role of Th1 cells?
Produce IL2 for inflammation, and IFNy and TNFa to activate macrophages for phagocytosis.
What is the role of Th2 cells?
Produce IL4 and 13 to activate B cells and promote class switching from IgM to IgE.
What are the stages of innate immunity?
1) Frontline defence (specialised, embedded cells and soluble factors in body fluids); 2) Immediate reinforcements (circulating cells and soluble molecules); 3) Recognition; 4) Elimination
Why is the point in inflammation?
To dilate the blood vessels for increased permeability and blood flow in order to allow immune cell migration to the infected area.
What is a common PAMP found on a parasite?
Soluble egg antigen glycosyl residues.
Name three DAMPs.
Phosphatidylserine, crystalline substances, and external chromatin.
What is the extracellular structure of TLR?
Extracellular domain is a horseshoe shape of Leu fish repeats, the inner surface is a B sheet and forms the ligand binding domain.
What immune cell is most sensitive to LPS?
The macrophage.
How is LPS binding to TLR4 regulated?
Binding of LPS to LPS, and then to CD14 on the host cell membrane makes TLR more sensitive. Binding of LPS to BPI prevents binding to TLR.
What does LPS binding induce in TLR?
The formation of TLR multidimers.
What is the MyD88 pathway?
MyD88 activates the protein kinase IRAK which causes IkB degradation, released NFkB into the nucleus. It immediately activates genes in the immune response via complex control mechanisms.
What is the TRIF pathway?
Causes nuclear translocation of IRF3 which results in the transcription of INFa/B. It has a slower effect for a calmer response.
