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Perio Exam 1 > Immunology 1 > Flashcards

Immunology 1 Flashcards

1
Q

how do bacteria induce damage to periodontal tissues?

A

bacteria attach and colonize the gingival crevice. some species can invade periodontal soft tissue
bacteria release substances that directly damage host cells
bacteria activate the host’s own inflammatory and immune systems, leading to host tissue damage

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2
Q

what are major microbial virulence factors?

A

ability to invade periodontal epithelium
direct cytotoxic effects of bacterial metabolic waste products
damaging bacterial enzymes
immunostimulatory molecules

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3
Q

what are the direct cytotoxic effects of bacterial metabolic waste products?

A

ammonia
indole compounds
fatty acids
hydrogen sulfide

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4
Q

what are the damaging bacterial enzymes?

A

leukotoxin (from aa kills leukocytes)

gingipains (arg specific proteases from pg)

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5
Q

what are the immunostimulatory molecules?

A 
lps from gram neg bacteria
lipoteichoic acid from gram positive bacteria
gingipains
formylpeptides
other surface antigens
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6
Q

what are the mechanisms of periodontal defense?

A

prevention of bacterial entry (passive protection by periodontal epithelium)
innate immune responses (nonspecific, first line of active defense)
acquired (adaptive immune responses (specific, second line of active defense)

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7
Q

what prevents bacterial entry?

A

shedding of epithelial cells into the oral cavity (inhibits bacterial colonization of mucosa)
intact epithelial barrier
positive fluid flow into the gingival crevice

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8
Q

what is the origin of gingival crevicular fluid?

A

gingival tissue interstitial fluid

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9
Q

what are the innate immune responses?

A

complement system
oral mucosa produces anti-microbial peptides (eg defensins)
oral epithelium produces pro-inflammatory cytokines
antimicrobial efect of antibodies, lactoferrin, lysozyme
phagocytic function of neutrophils (PMNs) and macrophages

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10
Q

what does the complement system do?

A

induces bacterial lysis
promotes phagocyte recruitment (chemotaxis)
promotes phagocytosis by opsonization of bacteria
helps activate mast cells, which increases vascular permeability

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11
Q

what are the proinflammatory cytokines produced by oral epithelium?

A

il-1beta and tnf alpha are universal signals of infection that help recruit inflammatory cells
il-8 attracts neutrophils in the early stages of infection

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12
Q

what is the adaptive or acquired immunity?

A

second line of defense
specific response to bacterial antigen
antigen recognition, immune memory and clonal expansion are hallmarks of adaptive immunity

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13
Q

what are the roles of toll like receptors?

A

major role induction of innate immune response
recognize conserved microbial-associated moelcular patterns (including LPS, lipoteichoic acid and flagellae)
expressed by all cells, including epithelial cells, PMNS, monocytes and macrophages
signal for cells to produce cytokines, chemokines, antimicrobial peptides, nitric oxide and eicosanoids

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14
Q

what are the biological activities of LPS?

A 
complement activation
PMN activation
macrophage activation
b-cell mitogen activity
pyrogenicity
stimulation of bone resorption
stimulation of prostaglandin synthesis
induction of tnf- alpha
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15
Q

what is the role of cytokines in innate immunity?

A

involved in coordination of inflammatory and immune responses
proinflammatory activity- il-1beta, tnf-alpha
chemotactiv activity- il-8

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16
Q

what is the role of prostaglandins in innate immunity?

A

derived from archidonic acid
produced by activated macrophages and other cells
prostaglandins (especially PGE2) induce vasodilation and cytokine production
PGE2 induces production of matrix metalloproteinases by fibroblasts and osteoclasts, which damage periodontal tissues

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17
Q

what is the role of matrix metalloproteinases in innate immunity?

A

degrade extracellular matrix
concentratins are higher in inflamed gingiva than in healthy gingiva
ex. PMN collagenase (degrades the major structural protein in gingiva)

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18
Q

what is the role of proteinase inhibitors in innate immunity?

A

antagonize inflammation

inhibit degradation of matrix proteins

19
Q

what is alpha 2- macroglobulin?

A

broad spectrum proteinase inhibitor

20
Q

what is alpha-1 antitrypsin?

A

broad spectrum proteinase inhibitor and potent inhibitor of PMN collagenase

21
Q

what are the antimicrobial peptides of innate immunity?

A

defensins and calprotectin

22
Q

what does defensins do?

A

inhibit bacteria and fungi. produced by salivary gland epithelium

23
Q

what does calprotectin do?

A

inhibits bacteria and fungi by chelating zinc. produced by epithelium, PMNS, monocytes, macrophages

24
Q

what are the cellular elements of innate immunity?

A

neutrophils (PMNs) are deployed from blood
macrophages are found in organs and tissues
mast cells are found throughout the body, esp in connective tissue subjacent to mucosal surfaces

25
Q

what does acute inflmmation of injury result in?

A

increasing vascular permeability, resulting in redness, edema and increased gingival crevicular fluid flow

26
Q

what is the role of PMN?

A

deliver antimicrobial substances to bacteria in the early stages of infection

27
Q

what are the pmn activities triggered by?

A

receptor binding events, phagocytosis, adherence, chemotaxis

28
Q

what are the oxidative mechanisms for bacterial killing by PMNs?

A

cytosol- 47 kdal phosphoproteins, 67 kdal protein
membrane specific, tertiary granule-cytochrome b, 65 kdal flavoprotein
azurophil granule- myeloperoxidase

29
Q

what are the nonoxidative mechanisms for bacterial killing by PMNs?

A

cytosol- calprotectin
specific granule- lactoferrin, cobalophilin, lysozyme
azurophil granule membrane- B/PI
azurophil granule- defensins, neutral serine proteases, lysozyme

30
Q

what does the PMN surface have?

A

high affinity receptors

31
Q

what is the role of innate immunity?

A

inherent biological responses

32
Q

what is the role of adaptive or acquired immunity?

A

based on recognition of antigens, immune memory and clonal expansion

33
Q

what is the cell proportions in chronic periodontitis?

A

number of plasma cells >b lymphocytes> t lymphocytes

34
Q

what functions as an antigen?

A

LPS, bacterial proteins or other compounds

35
Q

what functions as antigen presenting cells?

A

macrophages and langerhan cells

36
Q

what is the t-cell response?

A

t-cell receptor has 2 glyco proteins chains with variable segments
variable segments determine the type of immune response
2 types of t-helper cells- differ in cytokine profiles
cytokines are messenger proteins that transmit signals to other cells

37
Q

what are the cytokines regulate th1?

A

il-2, ifn gamma, tnf alpha

38
Q

what are the cytokines that regulate th2?

A

il-4, 5, 6, 10,13

39
Q

what is the hallmark of chronic periodontitis?

A

th1 and th2 balance

40
Q

what is the t cell response?

A

cytotoxic t cells activated by cytokines
cytotoxic t cells respond to intracellular pathogens
antigens from these pathogens bind MHC1 molecules
cytotoxic t cells recognize this antigen presentation and detroy infected cells
not many cytotoxic t cells are found in periodontitis, suggesting that viruses and invasive bacteria are not major players

41
Q

what is the b cell response?

A

humoral immunity (antibody mediated) triggered in response to soluble antigens
antigen-antibody complex activates complement
antigen-antibody complex facilitates opsonization
th-2 cytokines activate b cells to plasma cells

42
Q

what are the 2 types of b cells?

A

conventional: produce antibodies against bacteria, levels decrease in healthy and treated sites
autoreactive: produce auto-antibodies, levels do not decrease after treatment

43
Q

what is avidity?

A

antigen binding differs among antibody subclasses. not all are capable of effective opsonizaton or complement activation

44
Q

what is efficacy of b cell response?

A

igg2<igg1 in chronic periodontitis, but igg2 predominates in aggressive periodontitis
disease due to less effective antibody?
antigen recognition:igg2 recognizes carbohydrate antigens (lps), while other subclasses mainly recognize protein antigen

Perio Exam 1 (6 decks)

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