Host Responses to Periodontal Bacteria Flashcards
When acteria attach and colonize ___ ___ and invade periodontal soft tissue they induce damage to periodontal tissues.
gingival crevice
T/F. The bacteria release substances that directly damage host cells and activate the host’s own inflammatory and immune systems, leading to host tissue damage.
True
What are four categories of major microbial virulence factors?
- ability to invade periodontal epithelium
- direct cytotoxic effects of bacterial metabolic waste products
- Damaging bacterial enzymes
- immunostimulatory molecules
What bacterial waste products have direct cytotoxic effects?
ammonia
indole compounds
fatty acids (propionic and butyric acids)
hydrogen sulfide
___ from A. a kills leukocytes and ___ are Arg-specific proteases from P. g.
Leukotoxin; Gingipains
Immunostimulatory molecules include ___ (endotoxin) from gram-negative, ___ acids from gram-positives, gingipains (___-specific protease), ___ that stimulate leukocyte chemotaxis and other surface antigens.
LPS; Lipoteichoic; Arg; Formylpeptides
What is a passive protective defense mechanism by periodontal epithelium?
prevention of bacterial entry
What are two active protective defense mechanisms by periodontal epithelium?
innate and acquired (adaptive) immune responses
Prevention of bacterial entry involves ___ of epithelial cells into the oral cavity to inhibit bacterial colonization of mucosa, maintaining an intact epithelial barrier and ___ fluid flow into the gingival crevice.
shedding; positive
Gingival ___ fluid originates as gingival tissue ___ fluid.
crevicular; interstitial
In the blood vessels, what is associated with increased permeability? How does this happen?
inflammation
collagen of the basement membrane is degraded and plasma proteins are loss when junctions become leaky
The complement system is part of the ___ immune response and induces bacterial ___, promotes phagocyte recruitment (___) and phagocytosis by ___ of bacteria, and helps activate ___ cells, which increases vascular permeability.
innate; lysis; chemotaxis; opsonization; mast
The oral ___ produces anti-microbial peptides (e.g., defensins) and the oral epithelium produces pro-inflammatory ___.
mucosa; cytokines
___ and ___ are universal signals of infection that help recruit inflammatory cells and ___ attracts neutrophils in the early stages of infection.
IL-1ß; TNF-α; IL-8
T/F. The adaptive immune response uses Antimicrobial effect of antibodies, lactoferrin, lysozyme and phagocytic function of neutrophils (PMNs) and macrophages.
False, The INNATE immune response uses Antimicrobial effect of antibodies, lactoferrin, lysozyme and phagocytic function of neutrophils (PMNs) and macrophages.
What is the second line of defense is a specific response to bacterial Ag that utilizes Ag recognition (highly specific), immune memory, and clonal expansion?
adaptive or acquired immunity
T/F. Bacteria can only colonize subgingival environments.
False, they can colonize supra- and subgingival environments
The supragingival environment depends on saliva whose flow rate is ___ than gingival fluid in the subgingival environment.
faster
The idea is to clear the bacteria before they colonize.
saliva 0.4-2ml/min
gingival fluid 20ul/h
As part of the innate immune response, ___-___ receptors are found on the oral mucosal ___ and recognize ___ microbial-associated molecular patterns (including LPS, lipoteichoic acid and flagellae).
Toll-like; surface; conserved
Where are TLRs expressed?
on all cells, including epithelial cells, PMNs, monocytes and macrophages
What does the TLRs signal for cells to produce?
cytokines, chemokines, antimicrobial peptides, nitric oxide and eicosanoids
What types of cells release LPS (endotoxin)?
gram-negative bacteria
What are the biological activities of LPS (endotoxin)?
Complement activation PMN activation Macrophage activation B-cell mitogen activity Stimulation of bone resorption Stimulation of prostaglandin synthesis Induction of Tumor Necrosis Factor (TNF-α)
