host response to periodontal bacteria

Question 1

How do bacteria induce damage to periodontal tissues?

Answer 1

1) Bacteria attach and colonize the gingival crevice
2) Bacteria release substances that directly damage host cells
3) Bacteria activate the host’s own inflammatory and immune systems

Question 2

what are the 4 Major microbial virulence factors?

Answer 2

Ability to invade periodontal epithelium

Direct cytotoxic effects of bacterial metabolic waste products

Damaging bacterial enzymes

Immunostimulatory molecules

Question 3

what were the 2 Damaging bacterial enzymes listed as microbial virulence factors?

Answer 3

Leukotoxin (from A. a., kills leukocytes)

Gingipains (Arg-specific proteases from P. g.)

Question 4

give some examples of immunostimulatory molecules produced by microbes

Answer 4

1) LPS & Lipoteichoic acids from Gram-positive bacteria
2) Gingipains (Arg-specific protease)
3) Formylpeptides
4) Other surface antigens

Question 5

what are the Mechanisms of periodontal defense?

Answer 5

Prevention of bacterial entry

Innate immune responses

Acquired (adaptive) immune responses

Question 6

Shedding of epithelial cells into the oral cavity inhibits what?

Answer 6

bacterial colonization of mucosa

Question 7

in healthy individuals, there is a ________ fluid flow into the gingival crevice

Answer 7

positive

Question 8

what causes increased permeability in the periodontal capillaries?

Answer 8

Inflammation

Question 9

what effects does the Complement system (of the innate immune system) produce?

Answer 9

Induces bacterial lysis

Promotes phagocyte recruitment (chemotaxis)

Helps activate mast cells, which increases vascular permeability

Question 10

what are defensins? what are they produced by?

Answer 10

anti-microbial peptides produced by the oral epithelium

Question 11

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

Answer 11

IL-1ß and TNF-α

Question 12

_____ (a cytokine) attracts neutrophils in the early stages of infection

Answer 12

IL-8

Question 13

the Phagocytic function of neutrophils (PMNs) and macrophages are part of what type of immune response?

Answer 13

innate immune response

Question 14

what are the “hallmarks” of adaptive immunity?

Answer 14

Ag recognition, immune memory, and clonal expansion

Question 15

what category of molecules plays a major role in induction of innate immune response?

Answer 15

Toll-like receptors (TLRs)

Question 16

what types of molecules can toll-like receptors recognize?

Answer 16

LPS, lipoteichoic acid and flagellae

Question 17

TLR’s are expressed by what types of cells?

Answer 17

Expressed by all cells, including epithelial cells, PMNs, monocytes and macrophages

Question 18

what do TLR’s signal for cells to do?

Answer 18

signal for cells to produce cytokines, chemokines, antimicrobial peptides, nitric oxide and eicosanoids

Question 19

secretory IgA, lactoferrin, lysozymes and agglutinin are all released from what oral structure?

Answer 19

salivary glands

Question 20

LPS (an endotoxin) can cause the stimulation of _______

Answer 20

prostaglandin

Question 21

LPS induces ____

Answer 21

TNF-α

Question 22

what effect do membrane attack complexes have?

Answer 22

they punch holes in the cell membrane of microbes

Question 23

Pro-inflammatory activity is mediated by which cytokines?

Answer 23

IL-1β, TNF-α

Question 24

Chemotactic (recruitment of neutrophil) activity is mediated by what cytokine?

Answer 24

IL-8

Question 25

Prostaglandins are derived from ____________

Answer 25

arachidonic acid

Question 26

what cell type produces prostaglandins?

Answer 26

Produced by activated macrophages and other cells

Question 27

prostaglandins induce what effects?

Answer 27

vasodilation and cytokine production

Question 28

______ induces production of matrix metalloproteinases by fibroblasts and osteoclasts

Answer 28

PGE2 (a prostaglandin)

Question 29

_________ ______ Degrade extracellular matrix

Answer 29

Matrix metalloproteinases

Question 30

what an example of a Matrix metalloproteinases?

Answer 30

PMN collagenase (degrades the major structural protein in gingiva)

Question 31

t/f: Concentrations of matrix metalloproteinases are higher in inflamed gingiva than in healthy gingiva

Answer 31

true

Question 32

what is the function of proteinase inhibitors?

Answer 32

antagonize inflammation *INHIBIT degradation of matrix proteins*

Question 33

what is calprotectin? how does it work?

Answer 33

- antimicrobial peptide | - works by chelating zinc

Question 34

t/f: calprotectin is produced by epithelium, PMNS, monocytes and macrophages

Answer 34

true

Question 35

what are the 3 defense cells of innate immunity?

Answer 35

- neutrophils - macrophages - mast cells

Question 36

neutrophils release ___ and ___ to activate macrophages

Answer 36

C3a and C5a

Question 37

which cell type delivers antimicrobial substances to bacterial in the EARLY stages of infection

Answer 37

neutrophils (PMN's)

Question 38

what are the 2 general mechanisms for bacterial killing by PMN's?

Answer 38

oxidative and nonoxidative

Question 39

PMN activities are triggered by _______ ________ events

Answer 39

receptor binding

Question 40

t/f: the neutrophil surface has many high affinity receptors

Answer 40

true

Question 41

endothelial cells release what molecules in response to IL-1 and TNF alpha?

Answer 41

ICAM-1 and ELAM-1 | adhesion molecules- bind to neutrophils

Question 42

what are the steps in PMN extravasation?

Answer 42

random contact rolling sticking extravasation

Question 43

what anti-microbial factors are contained in PMN (neutrophil) granules?

Answer 43

lysozymes, elastase, pepsin, metalloproteases, hydrolases

Question 44

t/f: In chronic periodontitis, number of plasma cells is less than B lymphocytes and T lymphocytes

Answer 44

false In chronic periodontitis, number of plasma cells > B lymphocytes > T lymphocytes

Question 45

_________ present antigens to lymphocytes

Answer 45

macrophages

Question 46

t/f: in chronic periodontitis, there is a large number of innate immune cells present

Answer 46

false- there are more acquired immune cells

Question 47

Macrophages and Langerhans cells function as ________ during adaptive immunity

Answer 47

Ag presenting cells (APC)

Question 48

what is the structure of the T-cell receptor?

Answer 48

T-cell receptor has 2 glycoprotein chains (alpha and beta) with variable segments

Question 49

the _______ on T-cell receptors will determine the type of immune response

Answer 49

Variable segments

Question 50

Cytokines are ________ ________ that transmit signals to other cells

Answer 50

messenger proteins

Question 51

what cytokines are released by type 1 T helper cells

Answer 51

Th1: IL-2, IFN-gamma, TNF-alpha

Question 52

what cytokines are released by type 2 T helper cells

Answer 52

Th2: IL-4, 5, 6, 10, 13

Question 53

what molecule can regulate the balance between cell mediated immunity & antibody production?

Answer 53

IL-10 keeps the balance between Th1 and Th2 cell functions

Question 54

Cytotoxic T cells (Tc) are activated by _______

Answer 54

cytokines

Question 55

_____ cells respond to intracellular pathogens

Answer 55

Tc (cytotoxic T cells)

Question 56

what do Tc cells do?

Answer 56

they recognize this antigen presentation and destroy infected cells

Question 57

what does the lack of Tc cells in periodontitis suggest?

Answer 57

suggests that viruses and invasive bacteria are not major players

Question 58

what does the Ag-Ab complex activate? what does it facilitate?

Answer 58

activates complement facilitates opsonization

Question 59

what are the 2 types of B cells?

Answer 59

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

Question 60

which IG protein shows up first after an antibody exposure? which shows up second?

Answer 60

IgM shows up FIRST IgG shows up SECOND- but it has a much larger response

Question 61

what is the avidity of B cell responses?

Answer 61

Ag-binding differs among antibody subclasses. not all are cab able of effective opsonization or complement activation

Question 62

which immunoglobulin, IgG1 or IgG2, is higher in chronic periodontitis? aggressive periodontitis?

Answer 62

IgG1 is higher in CHRONIC IgG2 predominates in AGGRESSIVE periodontitis

Question 63

which Ig recognizes carbohydrate antigens (LPS)? what do the other subclasses recognize?

Answer 63

IgG2 recognizes LPS other subclasses recognize protein Ag (antigen)

Question 64

what is involved in lymphocyte "homing" in the periodontium?

Answer 64

periodontal specific lymphocytes "home" back to the periodontium and locate within the tissues where they begin their humoral and cell-mediated immune functions

Question 65

antibodies are produced locally by plasma cells which are controlled by _____ cells

Answer 65

Th2 (T helper type 2 cells)