host defenses Flashcards
mediators of innate immunity
complement system cytokines prostaglandins matrix metalloproteinases proteinase inhibitors antimicrobial peptides
cytokines involved in ____ of ____ and ____ responses
coordination; inflammatory; immune
pro-inflammatory cytokines
IL-1beta; TNF-alpha
cytokines with chemotactic activity
IL-8
prostaglandins (especially PGE2) induce ____ and _____
vasodilation; cytokine production
PGE2 induces production of _____ by fibroblasts and osteoclasts, which damage periodontal tissues
matrix metalloproteinases
matrix metalloproteinases degrade _____
extracellular matrix
_____ (a MMP) degrades the major ____ in gingiva
PMN collagenase; structural protein
proteinase inhibitors _____ inflammation and inhibit ____ of _____
antagonize; degradation; matrix proteins
broad spectrum proteinase inhibitor
alpha-2 macroglobulin
broad spectrum proteinase inhibitor and potent inhibitor of PMN collagenase
alpha-1 antitrypsin
inhibit bacteria and fungi; produced by salivary gland epithelium
defensins
inhibits bacteria and fungi by chelating zinc; produced by epithelium, PMNs, monocytes and macrophages
calprotectin
cellular elements of innate immunity
neutrophils (PMNs)
macrophages
mast cells
neutrophils are deployed from ____; macrophages are found in ___ and ____; mast cells found throughout the body, esp in ____ subjacent to mucosal surfaces
blood; organs; tissues; connective tissue
major microbial virulence factors
- ability to invade periodontal epithelium
- direct cytotoxic effects of bacterial metabolic waste products
- damaging bacterial enzymes
- immunostimulatory molecules
examples of bacteria able to invade pd epithelium
A.a. and P.g.
examples of bacterial metabolic waste products
ammonia, indole compounds, fatty acids (propionic and butyric acids), hydrogen sulfide
examples of damaging bacteria enzymes
- leukotoxin (from A.a., kills leukocytes)
- gingipains (Arg-specific proteases from P.g.)
examples of immunostimulatory molecules
- LPS (endotoxin) from gram-negative bacteria
- lipoteichoic acids from gram positive bacteria
- gingipains (Arg-specific proteases)
- formylpeptides (stimulate leukocyte chemotaxis)
- other surface antigens
mechanisms of periodontal defense
- prevention of bacterial entry (passive protection by periodontal epithelium)
- innate immune response (nonspecific, first line of active defense)
- acquired (adaptive) immune responses (specific, second line of active defense
prevention of bacterial entry by ____ of epithelial cells into the oral cavity; intact _____, and ____ into the gingival crevice
shedding (inhibits bacterial colonization of mucosa)
epithelial barrier
positive fluid flow
gingival crevicular fluid originates as _____
gingival tissue interstitial fluid
in the innate immune response, ____ is activated, oral mucosa produces _____, oral epithelium produces _____
complement system; anti-microbial peptides (defensins); pro-inflammatory cytokines (IL-1beta, TNF-alpha, and IL-8)
4 functions of the complement system
- induces bacterial lysis
- promotes phagocyte recruitment (chemotaxis)
- promotes phagocytosis by opsonization of bacteria
- helps activate mast cells, which increases vascular permeability
____ and ____ are universal signs of infection that help recruit inflammatory cells; ____ attracts neutrophils in the early stages of infection
IL-1beta; TNF-alpha; IL-8
antimicrobial effects of ____, ___, and ____ in the innate immune response along with phagocytic function of ____ and _____
antibodies, lactoferrin, lysozyme
neutrophils (PMNs) and macrophages
____, _____, and _____ are hallmarks of adaptive immunity
Ag recognition; immune memory; clonal expansion
TLRs signal for cells to produce:
cytokines, chemokines, antimicrobial peptides, NO, and eicosanoids
biological activities of LPS (endotoxin)
- complement activation
- PMN activation
- macrophage activation
- B-cell mitogen activity
- stimulation of bone resorption
- stimulation of PG synthesis
- induction of TNF-alpha
two complement proteins that can induce PMN chemotaxis and mast cell degranulation
C3a and C5a
complement protein that facilitates phagocytosis by opsonizing bacteria
C3b
in chronic periodontitis, number of ____ > _____ > _____
plasma cells > B lymphocytes > T lymphocytes
adaptive immune cells more prominent than innate immune cells
T cell receptor has two ____ (alpha and beta) with ____ segments
glycoprotein chains; variable
____ determine the type of immune response
variable segments
2 types of T helper cells differ in _____
cytokine profiles
cytokines are ______ that transmit signals to other cells
messenger proteins
Th1 cells produce:
IL-2, IFN-gamma, TNF-alpha
Th2 cells produce:
IL-4, 5, 6, 10, 13
_____ are activated by cytokines and respond to intracellular pathogens
cytotoxic T cells
Ags from intracellular pathogens bind ____ molecules; Tc cells recognize this antigen presentation and destroy infected cells
MHC I
not many Tc cells found in periodontitis , suggesting that ____ and ____ are not major players
viruses; invasive bacteria
humoral immunity ( _____ mediated) triggered in response to _____
antibody; soluble antigens
antigen-antibody complex activates ____ and facilitates _____
complement; opsonization
Th2 cytokines activate ____ to ____
B cells; plasma cells
2 types of B cells
conventional and auto-reactive
antibody mediated protection involves antibody plus ____ and antibody plus ____
complement; cells
3 functions of antibody alone
- blocks entry of toxins, viruses (IgM, IgG, IgA)
- immobilizes bacteria (IgM > IgG)
- agglutinates bacteria (IgM > IgG)
antibody plus complement ____ bacteria
lyses (IgM, IgG)
antibody plus cells ____ bacteria, fungi for ____
opsonizes; phagocytosis (IgG)
antibody plus cells activates _____
extracellular killing (IgG)
IgG2 < IgG1 in _____, but IgG2 predominates in _____
chronic periodontitis; aggressive periodontitis
IgG2 recognizes _____ antigens, while other subclasses mainly recognize _____ antigen
carbohydrate (LPS); protein
homing of _____ takes place within the periodontal lesion
relevant immune cells
____ cells outnumber ____ cells in chronic periodontal lesions
Th2; Th1
____ cells are among the most predominant and active secretory cells in advanced periodontal lesions
plasma
the ratio of IgG subclasses are similar in ____ and ____
serum; GCF
an individual’s ability to mount a specific ____ to bacteria in the _____ may indicate a patient’s susceptibility to the disease and ability to respond to treatment
antibody response; subgingival biofilm
