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54 Cards in this Set
- Front
- Back
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What aspects of the host defence are considered?
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saliva
gingival epithelium inflammation- non specific host response immune response- specific host response |
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How does saliva help prevent excessive plaque build up?
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by washing and swallowing bacteria
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What does saliva contain?
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IgA antibodies (inhibit attachement of bacteria)
antibacterial proteins e.g. peroxidase enzyme, lysosyme, lactoferrin |
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What is the role of antibacterial proteins in saliva?
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have potential in killing bacteria
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Saliva has a limited role for what kind of plaque bacteria?
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subgingival
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What do intact epithelial cells of gingiva present?
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a barrier to bacteria
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What do damaged epithelia cells secrete?
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chemical mediators that trigger inflammatory response
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What do the processes of inflammation and immune response allow for?
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bacteria to be destroyed
damaged tissue to be broken down and removed healing to occur |
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Inflammation and immune response are generally protective but most of the destruction in periodontal disease is though to be inadvertently caused by?
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components of the inflammatory and immune responses
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explain the inflammatory response flow chart
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damage to cells
chemical mediators released- leukotrines and prostaglandins inflammation leads to 2 parts 1- inflammatory exudate including complement components 2- cells attracted neutrophils first and then macrophages 1- serum complement component 2- cellular component |
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What are the 2 major pathways of activation for the serum complement system?
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Alternative- component binding to certain antigens, e.g. exotoxins
Classical- component binding to antibody, following antibody binding to bacterial cell wall....exposes a site on the antibody for the first complement component |
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What are some examples of complement components?
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Membrane attack complex (MAC)- end product, can destroy some bacterial cell walls
chemotaxins- for phagocytes- neutraphils and macrophages opsonins- coatings over anitgens (hat example) |
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How can periodontal tissue also be damaged?
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as a side effect of complement factors
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What are the main cells involved in phagocytosis in the cellular component?
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Neutrophils
Macrophages |
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When do neutrophils dominate?
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early on
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When do macrophages increase?
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after neutrophils, later
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Bacteria are engulfed within phagocytic cells and destroyed by a number of mechanisms, name a few?
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enzymes
peroxides |
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explain the neutrophils in the cellular component
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main cell in first line defence
move through JE into the crevice phagocytose bacteria- most affective in presence of opsonins and antibodies secrete enzymes onto bacteria/toxins secrete MMP's |
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What is MMP's?
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Matrix Metalloproteases- enzymes involved in tissue remodelling
collagenase and hyaluronidase |
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explain the macrophages in the cellular component
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more likely to remain in tissues
phagocytose secrete MMP's present antigens to lymphocytes...link to inflammatory and immune responses secrete mediators that influence the inflammatory and immune processes including prostaglandins and cytokines |
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What are cytokines?
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cell proteins produced by host cells
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how do cytokines transmit messages between cells?
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by activating receptors on cell membranes
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What cells produce cytokines?
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macrophages
lymphocytes fibroblasts osteoblasts/clasts |
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What do cytokine influence?
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inflammation, immunity, tissue turnover, growth and healing
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Are cytokines potent?
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yes, detected by receptors in very small quantities
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What influences production?
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complex feedback mechanisms
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What is interluikin?
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look up in perio manual
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Why is there an interest in cytokines and chemical mediators?
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thought to play a role in the destruction of the periodontal tissues
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What are the pro-inflammatory cytokines and mediators?
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TNF, IL-1, IL-6, IL-17, PGE2
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What can these cytokines and mediators trigger?
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enzyme (MMP) release from a range of cells which can then trigger break down of fibrous tissue
OR RANKL secretion/ expression from range of cells which can trigger osteoclast activity which can cause bone resorption |
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When does the specific response occur?
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subsequent to exposure to an antigen
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antigens are presented to what type of cells?
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naive T-helper cells
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What are the antigen presenting cells?
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macrophages and Langerhauns cells
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What are the different subsets of T-helper cells?
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Th1
Th2 Th17 Treg cells They all lead to different responses |
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Explain the response of Th1
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cell mediated-->cytokines-->macrophages-->cytokines
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Explain the response of Th2
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humoral-->cytokines-->B-cells-->cytokines-->plasma cells-->antibodies
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Explain the response of Th17
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inflammation-->cytokines-->neutrophils-->cytokines
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Explain the response of Treg
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immune suppression-->cytokines-->cytokines
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What does the response of T-helper cells depend on?
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antigen type
previous exposure genetics |
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What tend to be the most numerous cells in the tissues of established CIPD lesion?
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B cells and plasma cells from Th2
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What does the humoral response rely on?
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circulating antibody- increased levels of specific antibody occur in crevicular fluid after a few weeks
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How do the antibodies of the humoral response exert protective effects?
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prevent bacteria from attaching to oral surfaces
neutralize bacterial toxins and tissue destroying enzymes opsonize bacteria for enhanced phagocytosis by neutrophils and macrophages form antibody-antigen complexes that trigger complement activation |
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When is host antibody especially protective?
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when it aids clearance by complement and neutrophils
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Plasma cells can produce a range of cytokines what ones protect against tissue destruction?
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IL-10
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What cytokines enhance tissue destruction?
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TNFa, IL-6
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What is RANKL?
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a cytokine that kickstarts osteoclasts, bone resorption
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What cells may produce RANKL?
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B cells in response to bacterial stimulation
T cells may also |
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Large amounts of IL-1 or TNF can stimulate what?
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collagenase
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What are key cells involved in cell mediated?
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Th1 and macrophages
cytokines produced by Th1 cells activate macrophages to destroy phagocytosed pathogens |
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What is a recent finding?
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awareness of Th17
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Where are Th17 found?
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at the interfaces between the external and internal environment e.g. lining the GI tract and skin
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What do Th17 secrete?
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cytokines, e.g. IL-17 which promotes neutrophil attraction
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What might IL-17 do?
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promote RANKL expression on other cells e.g osteoblasts and fibroblasts
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What does TGF stand for?
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tissue growth factor
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