Host Response to Periodontal Bacteria Flashcards
(41 cards)
How do Bacteria induce damage to periodontal tissues?
- Bacteria attache and colonize the gingival crevice, some species invade periodontal soft tissue.
- Bacteria release substances that directly damage host cells.
- Bacteria activate the host’s own inflammatory systems leading to host tissue damage.
What are the 4 Major Microbial virulence factors?
- Ability to invade periodontal epithelium
- Direct cytotoxic effects of bacterial metabolic waste products ( ammonia, indole compounds, hydrogen sulfide)
- Damaging bacterial enzymes (leukotoxin and Gingipains)
- Immunostimulatory molecules
- LPS (endotoxin) from gram -
- Lipoteichoic acids from gram +
- Gingipains
- formylpeptides
- other surface antigens
What are the main mechanisms of periodontal defense?
- Prevention of bacterial entry
- Innate immune response (nonspecific, first line of defense)
- Acquired immune response (specific, second line of defense)
How can bacterial entry be prevented?
- Shedding of epithelial cells in oral cavity (happens fairly rapidly) and gets rid of attached bacteria
- Intact epithelial barrier
- Positive fluid flow into the gingival crevice
Gingival crevicular fluid originates as _________.
gingival tissue interstitial fluid
Inflammation is associated with increased ______.
Permeability
How does the innate immune response respond to bacteria?
- Complement system = induces bacterial lysis through phagocytosis and activates most cells
- Oral mucosa produces anti-bacterial peptides (Defensins)
- Oral epithelium produces pro-inflammatory cytokines
- Antimicrobial effect of antibodies, lactoferrin, lysozyme.
- Phagocytic function of neutrophils (PMN’s) and macrophages
How does the adaptive or acquired immunity respond to bacteria?
- Specific response to bacterial antigen
- Antigen recognition, immune memory and clonal expansion are hallmarks of adaptive immunity
Can bacteria colonize both supra and sub gingival environments?
Yes.
What do Toll-like receptors do?
Major role in induction of innate immune response
- Recognize conserved microbial-associated molecular patterns including LPS.
- TLR’s signal for cells to produce cytokines, chemokines, antimicrobial peptides, nitric oxide and eicosanoids
What cells express TLR’s?
Almost all cells
What are the biological activities of LPS?
- Complement activation
- PMN activation
- Macrophage activation
- B-cell mitogen activation
- Pyrogenicity
- Stimulation of bone resorption
- stimulate prostaglandin synthesis
- induction of Tumor Necrosis factor
What are the mediators of innate immunity?
Cytokines and Prostaglandins
What do Cytokines do in regards to innate immunity?
Cytokines = involved in the coordination of inflammatory and immune response.
- Pro-inflammatory activity: IL-1, TNF-alpha
- Chemotactic activity: IL-8
What do prostaglandins do in regards to innate immunity?
- Induce vasodilation and cytokine production
- Induces production of matrix
What are defensins made by? What does it do?
Saliary glands…..
What do Matrix Metalloproteinases do in regards to innate immunity?
- Degrade extracellular matrix
* Concentrations are higher in inflamed gingiva than in healthy.
What do Proteinase inhibitors do in regards to innate immunity?
- antagonize inflammation
- inhibit degradation of matrix proteins
What are the main 2 Proteinase inhibitors?
Alpha-2 macro globulin = broad spectrum proteinase inhibitor.
Alpha-1 antitrypsin = broad spectrum proteinase inhibitor and potent inhibitor of PMN collagenase.
***What are the 2 most important Antimicrobial peptides in regards in innate immunity?
- Defensins
2. Calprotectin
What does Defensins do?
Inhibit bacteria and fungi
Where is Defensins produced?
Salivary gland epithelium
What does Calprotectin do?
Inhibits bacteria and fungi by chelating Zinc.
Where is Calprotectin produced?
By epithelium, PMNS, monocytes and macrophages
