Host Response to Periodontal Bacteria Flashcards Preview

AU 15- Periodontology > Host Response to Periodontal Bacteria > Flashcards

Flashcards in Host Response to Periodontal Bacteria Deck (91):
1

What are the four major microbial virulence factors?

1. Ability to invade periodontal epithelium
2. Damaging bacterial enzymes
3. Immunostimulatory molecules
4. Direct cytotoxic effects of bacterial metabolic waste products.

2

Which bacterial species are known to be good invaders of the periodontal epithelium?

A.a
P.g

3

_______ are Arg-Specific Proteases that are associated with P.gingivalis.

Gingipains

4

_____ from gram negative bacteria and ______ from gram positive bacteria are immunostimulatory molecules (virulence factors).

LPS
Lipoteichoic Acids

5

Which immunostimulatory molecule is produced by bacteria and stimulates leukocyte chemotaxis?

Formylpeptides

6

What are three mechanisms of periodontal defense against pathogenic bacteria?

1. Prevention of bacterial entry (Passive protection)
2. Innate Immune Response (non-specific, first line)
3. Acquired/Adaptive Immune Response (specific, second-line, antibody)

7

Shedding of _______ into the oral cavity inhibits bacterial colonization of mucosa (passive protection).

epithelial cells

8

How does "positive fluid flow" act as a passive protective mechanism of periodontal defense?

GCF starts in the capillaries of the connective tissue and flows through the junctional epithelium in order to clear the pocket/gingival crevice. This countercurrent discourages bacterial adherence

9

Gingival crevicular fluid originates as ________ fluid.

gingival tissue interstitial

10

Inflammation is associated with increased _______.

Permeability (leakage of proteins through gaps)

11

Epithelial cells are attached by _______ that will lose their integrity in the case of inflammation.

tight junctions

12

Which line of defense includes the complement system, defensins, and cytokines?

Innate Immunity (first line of defense)

13

What are defensins?

anti-microbial peptides

14

_____ and _____ are universal signals of infection that help recruit inflammatory cells.

IL-8
TNF-alpha

15

Which cytokine is responsible for attracting neutrophils in the early stages of infection?

IL-8

16

________ function of neutrophils (PMNs) and macrophages is part of the innate response.

Phagocytic

17

What is the purpose of the complement system?

C3a and C5a molecules act to recruit phagocytes, opsonize bacteria, activate mast cells, and eventually lyse bacterial cells more quickly.

18

Ag recognition, immune memory, and clonal expansion are hallmarks of ________ immunity.

adaptive (specific)

19

True or False: The flow rate of crevicular fluid is greater than that of saliva.

False. Saliva is much greater.

20

How does innate immunity play a major role in defense of the oral cavity?

By clearing bacteria before they colonize and by
releasing antimicrobial peptides and histamines

21

_______ play a major role in induction of the innate immune response.

TLRs

22

True or False: TLRs are expressed by all cells; including epithelial cells, PMNs, monocytes, and macrophages.

True

23

What is the action of TLRs?

They signal for cells to produce cytokines, chemokines, antimicrobial peptides, nitric oxide, and eicosanoids. Major role in induction of the innate immune response.

24

LPS is a gram_____ bacterial virulence factor that activates _______.

negative
the complement system, PMNs, macrophages, and B-cell mitogen activity

25

True or False: LPS (endotoxin) stimulates bone resorption and prostaglandin synthesis.

True

26

______ induces Tumor Necrosis Factor Alpha.

LPS

27

Within the complement system, the classic pathway is activated by _______ and the alternate pathway is activated by _______.

bacterial antibody
contact with a bacterial cell wall

28

What is the end result of complement activation?

Enhanced swelling (inflammation)
Opsonization of bacteria/Phagocytosis
Formation of the attack complex/Lysis

29

Which cells will produce cytokines (3)?

Macrophages
Bone cells
Fibroblasts

30

Which two important cytokines are pro-inflammatory?

IL-1 and TNF-alpha

31

Which cytokine is primarily responsible for chemotactic activity?

IL-8

32

_______ are mediators of innate immunity.

Prostaglandins

33

From what are prostaglandins derived?

metabolism of arachidonic acid

34

Prostaglandins induce _______ and cytokine production.

vasodilation

35

PGE2 is a prostaglandin that induces the production of matrix _________ by fibroblasts and osteoclasts which damages periodontal tissue.

metalloproteinases

36

Which cells produce matrix metalloproteinases?

fibroblasts
osteoclasts

37

True or False: Matrix metalloproteinase concentration is higher in inflammed gingiva than in healthy ginigiva.

True

38

Which matrix metalloproteinase is responsible for degrading the major structural protein in gingiva?

PMN collagenase

39

Why would the host want to degrade its own collagen matrix via metalloproteinase?

to allow neutrophils to gain better and quicker access

40

What is the action of proteinase inhibitors in innate immunity?

to antagonize inflammation by inhibiting degradation of matrix proteins; Alpha2 macroglobulin and Alpha1 antitrypsin

41

Name two important antimicrobial peptides that mediate the innate response.

Defensins
Calprotectin

42

______ are produced by salivary gland epithelial cells in order to inhibit bacteria and fungi.

Defensins

43

_______ is produced by epithelial cells, PMNs, monocytes and macrophages to inhibit bacteria and fungi.

calprotectin

44

How does calprotectin inhibit bacteria and fungi?

by chelating zinc

45

_____ cells release vasoactive amines in order to change the permeability of capillaries. They are found in connective tissue around mucosal surfaces.

Mast

46

PMNs are made in _______ and deployed from the blood to assist with innate immunity.

bone marrow

47

Acute inflammation or injury ______ vascular permeability, resulting in redness, edema, and increased ________ flow.

increases
gingival crevicular fluid

48

Cleavage products ____ and ____ of the complement system will activate mast cells and release histamine, Nitric Oxide, ____ and _____.

C3a
C5a
IL-1
TNF-alpha

49

What will bacterial LPS stimulate? What is LPS?

Stimulation of macrophages
Lipopolysaccharide endotoxin present in bacteria

50

What are the four mechanisms for antimicrobial release from PMNs in the early stages of infection?

1. Secretion
2. Respiratory burst (H2O2 causes dna damage)
3. Phagocytosis (efficient; granule filled lysosome)
4. Lysis or apoptosis (worse case scenario)

51

Mechanisms of bacterial killing by PMNs can be either ______ or ______.

oxidative
non-oxidative

52

What does elastase degrade?

extracellular matrix

53

How is a chemotactic gradient established adjacent to the junctional epithelium?

Neutrophils leave post-capillary venules through gaps in the endothelial cells. They then travel through the connective tissue toward the junctional epithelium and crevice. Chemotactic molecules are highest near the JE.

54

Which chemotactic molecules are most important in attracting PMNs?

LTB4, IL8, fmet-leu-phe, and C5a

55

A leukocyte contacts, _____, _____, and then extravasates out of a blood vessel prior to reaching the site of inflammation.

rolls, sticks

56

PMN extravasation involves ______molecules for adhesion and _______ molecules which bridge the gap between cells and extracellular matrix.

e-selectin
integrin

57

PMNs release granules which contain what kind of mediators?

Microboidal enzymes, serine proteases, metalloproteases, and acid hydrolases

58

In chronic periodontitis, is the number of plasma cells less than or greater than B lymphocytes?

Plasma cells > B lymphocytes

59

In chronic periodontitis, is there a greater proportion of B or T lymphocytes?

more B than T

60

In chronic periodontitis, which cell type makes up about 50% of the cells in the periodontal lesion?

plasma cells

61

True or False: LPS, bacterial proteins, or other compounds can serve as an antigen.

True

62

Macrophages and _______ cells function as Antigen Presenting Cells.

Langerhans

63

How many glycoprotein chains does a T-cell receptor have? What are the types?

two
alpha and beta

64

The alpha and beta glycoprotein chains have _______ that determine the type of immune response.

variable segments

65

True or False: T-cell receptors are different between chronic and aggresive periodontitits.

True

66

What are cytokines?

messenger proteins that transmit signals to other cells

67

What do Th1 cytokines regulate?

cell mediated immunity (IL-2, IFN-gamma, TNF-alpha)

68

What do Th2 cytokines regulate?

proliferation of B cells (IL-4,5,6,10,13)

69

The balance between stable and progressive periodontitis rests on which cytokine?

IL-10

70

High levels of IL-10 is associated with _____ progressive periodontitis.

less

71

What do Tc Cells do when they recognize MHC class 1 bound to antigen?

they destroy the infected cell

72

Are Tc Cells commonly found in periodontitis?

No, not many Tc Cells are found which suggests that viruses and invasive bacteria are not major players

73

Humoral immunity is triggered in response to _______.

soluble antigens

74

Ag-Ab complexes will activate ______ and facilitate ______.

complement
opsonization

75

Th2 cytokines (IL4,5,6,10,13) activate B cells to ______.

plasma cells

76

What are the two types of B cells?

conventional
autoreactive

77

What are conventional B cells?

they produce antibodies against bactera; levels decrease in healthy and treated sites

78

What are autoreactive B cells?

they produce auto-antibodies; levels do not decrease after treatment

79

After a B cell is activated by an antigen, what are its three fates?

1. becomes memory cells specific to that antigen
2. secretes antibody to that antigen
3. becomes plasma cells that will make antibody to that antigen

80

What is avidity?

Ag-binding differs among antibody subclasses; not all are capable of effective opsonization or complement activation

81

Which is more common in chronic periodontitis, IgG1 or IgG2?

IgG1

82

Which is more common in aggressive periodontitis, IgG1 or IgG2?

IgG2

83

Which is less effective, IgG1 or IgG2?

IgG2

84

What is different about antigen recognition in IgG2 compared to other subclasses?

IgG2 recognizes carbohydrate antigens (LPS)

most others recognize protein antigen

85

Periodontal microbe specific antibodies are produced by plasma cells within the _______ and travel back to the gingiva via blood vessels.

Lymph nodes

86

Antibodies are produced locally by _____cells which are controlled by type ____ helper cells; cell-mediated immune activity is regulated by type____ helper cells.

plasma
antibody (type 2)
cell-mediated (type1)

87

_______ of relevant immune cells takes place within the periodontal lesion.

Homing

88

______ cells are among the most predominant and active secretory cells in advanced periodontal lesions.

Plasma

89

True or False: the ratio IgG subclasses are similar in serum and GCF.

True

90

True or False: An individual's ability to mount a specific Ab response to bacteria in the subgingival biofilm does not indicate a patient's susceptibility to disease or ability to respond to treatment.

False

91

_______ are essential polysaccharides and polynucleotides that differ little from one pathogen to another but are not found in the host.

PAMPS