Innate Immunity Flashcards
Name some features of innate immunity?
-“inbuilt”, present from birth -not enhanced by second exposure (has no memory) -Uses cellular and soluble components Rapid response,minutes to hours, cooperates with and directs adaptive immunity
Recall the physical barriers used by the immune system in host defence?
Anatomical(physical) Skin-mechanical barrier, acidic environment Mucous membranes- mucus secretions trap microorganisms, cilia expel microorganisms
Recall the chemical (physiological) barriers used by the immune system in host defence?
-Body temperature/fever -Low pH- acidic pH of stomach kills many ingested microorganisms -Chemical mediators-lysozyme, interferons,complement
What does inflammation do?
local vascular permeability increases
Name the different tyoes of innate immunity defensive barriers?
Anatomical(physical) Physiological Phagocytic Inflammatory
Name the different cell types of the immune system?
Nuetrophil Eosinophil Dendritic cell Mononcyte/macrophage Basophil Mast cell Natural killer cell Never Ever Did My Baby Meet Norman
Name the function and mechanism of Neutrophils?
Phagocytosis and killing microbes
Name the function and mechanism of Eosinophil?
Phagocytosis,granule release, defence against parasitic infections and help B cell responses in GALT (IgA production) and involved in allergies
Name the function and mechanism of Basophils?
Granule release, may act as APC for “type 2 immunity” also involved in allergies and the release of histamine (hay fever)
Name the function and mechanism of monocyte/macrophages?
Phogocytosis,killing, cytokine release act as APC (antigen presenting cell)
Name the function and mechanism of Mast Cells?
Granule release (pro- inflammatory)
Name the function and mechanism Dendritic cell?
Antigen capture and presentation
Name the function and mechanism of Natural killer cells?
Lysis of infected cells
Name major features of nuetrophils?
(polymorphonuclear leukocyte) 40-75% of leukocytes; short lived cells, circulate in blood then migrate into tissues; first cells to be recruited to a site of tissue damage/infection
Name the major features of macrophages?
less abundant, dispersed throughout the tissues; signal infection by release of soluble mediators
To fight infection neutrophils need to….
- move from circulation into tissues to site of infection 2. bind pathogen 3. phagocytose pathogen 4. kill pathogen
What is opsonisation?
opson = greek for a sauce or relish coating of micro-organisms with proteins to facilitate phagocytosis opsonins are molecules that bind to antigen, and also can be bound by phagocytes antibody and complement function as opsonins
Name some oxygen-independent killing mechanisms for nuetrophils?
enzymes lysozyme hydrolytic enzymes antimicrobial peptides (defensins)
Name some oxygen-dependent killing mechanisms for nuetrophils?
respiratory burst: superoxide anion hydrogen peroxide singlet oxygen hydroxyl radical reactive nitrogen intermediates nitric oxide
How can nuetrophils form Neutrophil Extracellular Traps?
Activated neutrophils release granule proteins and chromatin to form extracellular fibres
What do mast cells release?
Secrete histamine and other inflammatory mediators, including cytokines
What can activate Mast cells?
What do Mast cells Lead to?
Leads to vasodilation and increased vascular permeability
Can Mast cells recognise, Phagocytose and kill Bacteria?
Yes
What are Natural Killers cells important for?
Important in defence against tumour cells and viral infections (esp.herpes)
Are natural killer cells Large granular lymphocytes?
yes