innate immunity periodontal diseases

1. Innate Immune Response
in Periodontal diseases
By: Reyam Ahmed Binbarek

2. Outlines
Definition of Innate immune
system.
Components and their Mechanism.

3. Immunity : All the mechanisms used by the
body to protect itself against all things
foreign.
Innate
immunity.
Acquired
immunity

4. Definition
 The term innate immunity refers to the
elements of the immune response that
are determined by inherited factors
 have limited specificity,
 fixed” in what they do.
 do not change or improve during an
immune response or as a result of
previous exposure to a pathogen.

5. Function of Innate Immunity
 Killing invading microbes
 Activating the acquired (adaptive immunity)

6. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity
 Linking Pathogenesis to Clinical Signs of Disease

7. - chemical barrier
(e.g.: antimicrobial peptides)
- physical barrier
e.g. (Tight junction &
rapid turnover)
Functions of epithelia in innate immunity
-Release cell signaling
molecules (e.g. :IL-1,IL-6,IL-
8,TNF alpha ,PGE2)

8. Antimicrobial Peptides
 Antimicrobial peptides are small, polycationic
peptides that disrupt bacterial cell membranes and
thereby directly kill bacteria with broad specificity.
 Epithelial cells constitutively express antimicrobial
peptides (e.g., hBDs, cathelicidins LL-37)
 Neutrophils are also a source of antimicrobial
peptides (i.e., α-defensins).

9. Expression sites of AMPs
AMP
tongue
Epitheliu
m
salivary
glands
connectiv
e tissue
leukocytes

10. AMP: has wider role in regulating innate and adaptive immune
responses to infection.
Stimulate mast cell
degranulation and
cytokine production.
Have a role in
wound healing
Has possible role in
therapy for oral
inflammatory diseases.

11. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity

12. Gingival Crevicular Fluid GCF
 GCF originates from the postcapillary venules
of the gingival plexus
It has a flushing action
in the gingival crevice
bring the blood
components ‘serum’ (e.g.,
neutrophils, antibodies,
complement components)
of the host defenses into
the sulcus.
The flow of GCF
increases in
inflammation

13. Saliva
 Saliva that is secreted from:
numerous minor
salivary glands
The action of saliva flow
preventing the attachment of
bacteria to the dentition
and the oral mucosal surfaces.
Function in innate
immunity:

15. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity
 Linking Pathogenesis to Clinical Signs of Disease

16. Complement Cascade
20 serum glycoprotein's
Circulating inactive in blood stream
When activated have profound &
powerful effects in stimulating
inflammation (pro-inflammatory
effects)

17. Complement Cascade
Functions:
 Recruitment of more phagocyte to area of infection
 Facilitate binding of phagocyte to bacteria (Opsonisation)
 Cause bacterial killing (cell lysis)
Hajishengallis, George, et al. 2015 "Complement involvement in
periodontitis: molecular mechanisms and rational therapeutic
approaches.
Pathways:
 Alternative pathway : activated directly by bacterial
endotoxin (LPS).
 Classical pathway: activated by formation of antigen-
antibody complexes

18. Alternative Pathway

19. Late stage of alternative pathway

20. C5-9 =MAC
membrane
attack complex
Chemotaxis of
phagocyte
Opsonaziation

21. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity

22. Cell Signaling Molecules
 Some stimulate cells to release other
molecules (cytokines)
 Some attract cells to areas of infection
(chemokines)
 Other stimulate cells to perform other
function (lymphokines)

23. Cell Signaling Molecules
 Epithelial cells also secrete a range of cytokines in
response to periodontal bacteria
IL-1 Chemokine
TNF-a PGE2

24. Cell Signaling Molecules

25. Interleukin-1 Family Cytokines.
 IL-1β
 plays a key role in inflammation and immunity
 it is closely linked to the innate immune response,
 it induces the synthesis and secretion of other mediators that
contribute to inflammatory changes and tissue damage.
IL-1β stimulates the synthesis of:
 PGE2,
 platelet-activating factor,
 nitrous oxide, thereby
 chemokine CXCL8
 ICAM-1 on endothelial cells
Vascular changes
Increasing blood flow
facilitating the infiltration of neutrophils
mainly produced by Monocytes, Macrophages, Neutrophils,
fibroblasts, keratinocytes, epithelial cells, B cells, and osteocytes
IL-1β synergizes with other pro-inflammatory cytokines
and PGE2 to induce bone resorption.

26. Tumor Necrosis Factor-α.
Secreted by Macrophages as well as by other
cell types, in response to bacterial LPS.
Macrophages
Endothelial cells
Activation By LPS
TNF-a
E-Selectin
facilitate
leukocyte
recruitment
Stimulate
secretion
Activated
Stimulate
secretion

27.  TNF-α although it possesses similar activity to IL-1β
but has a less potent effect on osteoclasts, and it is
present at lower levels in inflamed gingival tissues
than IL-1β.
 GCF levels of TNF-α increase as gingival
inflammation develops, and higher levels are found
in individuals with periodontitis

28. Clinical importance
 The importance of TNF-α and IL-1β in
periodontal pathogenesis is unquestioned,
and it has particularly been highlighted by
studies showing that the application of
antagonists to IL-1β and TNF-α resulted in
an 80 % reduction in recruitment of
inflammatory cells in proximity to the
alveolar bone and a 60% reduction in bone
loss. Assuma, R., et al.(1998)

29. The chemokine
Interaction between
bacteria and
keratinocytes
Up-regulation
of IL-8 &
ICAM-1
Stimulate
Neutrophil
migration
• Immune responses,
• Repair &inflammation,
• Regulate osteoclast activity by influencing myeloid
cell differentiation into osteoclasts
They also play important role in :

30. Clinically importance
 The chemokine CXCL8 (IL-8), has been demonstrated to
be localized in the gingival tissues in areas of plaque
accumulation and in the presence of neutrophil
infiltration, and it has also been found in GCF.
 Similar chemotactic gradients are also present in the
gingiva of periodontally healthy individuals, which
suggests a role for this process in the maintenance of
periodontal health and which supports the findings of
infiltrating neutrophils being present even in clinically
healthy tissues. By Tonetti MS et al (1998),

31. Clinically importance cont.
 CCL2 and CCL5 (RANTES ) play a role in
macrophage migration.
 CCL3 (MIP- 1α ) and CXCL10 play a role in T-cell
migration in inflamed periodontal tissues.Silva, T.
A., et al. (2007)
Haytural, O., et al.2015 "Impact of periodontitis
on chemokines in smokers.

32. Prostaglandin E2.
 The prostaglandins, including PGE2, are derived
from the COX pathway of arachidonic acid
metabolism. There are two main iso-forms of the
COX enzyme: COX -1 and COX -2.
COX -1: is constitutively expressed and has anti-
thrombogenic and cyto-protective functions.
COX -2: is induced after stimulation with various
cytokines, and LPS.

33. Prostaglandin E2.
PGE-2:
• Increase vascular
permeability
• Increase vasodilatation
• Increase PMNL chemotaxis
• Stimulate bone resorption

34. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity
 Linking Pathogenesis to Clinical Signs of Disease

35. Vasoactive peptides
Vasoactive peptides like histamine play crucial role in
development of inflammation.
Histamine
 released from mast cells upon stimulation by complement C3A and
C5A or PGE2 & cause vasodilatation .
 Increase vascular permeability to allow entrance of defense product
to the tissues
Vasodilatation:
 bring more blood cells and plasma proteins (complement , antibody)
 Slow down blood flow allowing PMNLs to touch vessel walls

36. Vasoactive peptides

37. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity
 Linking Pathogenesis to Clinical Signs of Disease

38. Adhesion Molecules
 Adhesion molecules used to stick to each other
or to components of the intercellular matrix
 Examples :
 intercellular adhesion molecules I and II (ICAM-1 and II)
 endothelial adhesion molecule I (ELAM-1)
 E-selectin
 Leukocyte function antigen 1 (LFA-1)
Expression of these molecules may turn of or
on by cytokine (IL-1 & IL-10)

39. Sequences of Adhesion
 Rolling:
 slowing down of PMNL due vasodilatation
 Make and break contacts between PMNL and vascular
endothelial cells
 Margination: as slowing down receptor binding
become stronger and PMNL become immobilized by:
adhesion of integrin molecules e.g. LFA-1 with
complentary endothelial receptor e.g. ICAM-I
 Diapedesis: allow PMNL to pass through leaky
vessels wall and enter tissues.
 Chemotaxis: by IL-8 and bacterial

41. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity
 Linking Pathogenesis to Clinical Signs of Disease

42. Phagocytes
 Professional phagocytic cells Neutrophils and Macrophages
These cells have phagocytic receptors
External receptor: FcR, CR3, Mannose receptor,TLRs
Internal receptors: TLRs
PAMP
Pathogen-associated
molecular patterns,

44. Neutrophil
 Present in blood (55-60% of WBC)
 Have short life (24hours)
Once PMNL arrives at the site of infection it kills
bacteria by intercellular (oxidative & non-oxidative)
and extracellular methods

45. Mechanism of Action

46. Non-Oxidative

47. Oxidative killing

48.  Enzymes: lysozymes dissolve cell wall of some bacteria
 Acid hydrolyses: digest bacteria
 Proteins: lactoferrin
 Peptides: Defensins direct killing
 Oxygen-derived products:
 O 2 - , H 2 O 2 & Myeloperoxidase
 Nitrogen-derived products
 NO (nitrogen oxide)
 Produced by inducible NO synthase (iNOS) enzyme
 Enzyme is induced by cytokines (LT, TNF )
 Lucarini, Guendalina, et al. (2016) "Uncoupling of Vascular Endothelial
Growth Factor (VEGF) and Inducible Nitric Oxide Synthase (iNOS) in
Gingival Tissue of Type 2 Diabetic Patients.

49. Clinically importance
 The importance of neutrophils to the maintenance of periodontal
health is demonstrated clinically by the observations of severe
periodontitis in patients with neutrophil defects
such as
 Neutropenia,
 leukocyte adhesion deficiency (LAD-1),
 Chediak-Higashi syndrome,
 Papillon-Lefèvre syndrome,
 chronic granulomatous disease (CGD),
( are often related to severe and early-onset forms of
periodontitis) Del Fabbro, M., et al. (2000)

50. Macrophages
 Blood: monocyte (1-5% WBCs)
 Tissues: Macrophages
 Mature form of monocyte
 Normally found in tissues
Function similar as PMNLs
but also act as APCs
 Produce cytokines/chemokine
bridging gap
between innate
& acquired
immunity
APCs
Phagocytosis

51.  N.b :
 Excessive and inappropriate or
dysregulated immune responses lead to
chronic inflammation and the
concomitant tissue destruction
associated with periodontal disease.
Bystander
damage

52. Components of innate immunity
 Intact epithelial barriers
 Lubrication of epithelium with fluids (saliva , GCF)
 Complement cascade.
 Cell signaling molecules
 Vasoactive peptides
 Adhesion molecules
 Cells of innate immunity
 Linking Pathogenesis to Clinical Signs of Disease

53. Linking Pathogenesis to Clinical Signs of
Disease
Epithelium
Physical barrier
Chemical barrier
Release cytokines
Further invasion
of bacteria
Defensins LL-37
Determine the outcome of
host-microbial interaction
Chemokines
Attract
Neutrophilsrelease

54. Linking Pathogenesis to Clinical Signs of
Disease Cont’
If the bacterial
challenge persist
Cellular & fluid
infiltration
continue
Neutrophils
MMPs
Lysozyme
Cytokines
ROS
Deeping of
the pocket
detachment
of cells at the
coronal
aspect of the
junctional
epithilum
epithelium
proliferates
lead to
necrosis of
epithelial
that distant
from C.T
pocket
epithelium
becomes
thin &
ulcerated &
bleeds more
readily,
results in
more B.O.P
• Breakdown of
collagen
• Tissue damage
• Fibroblast loss
ability to repair

56. Linking Pathogenesis to Clinical Signs of
Disease Cont’
Advancing
inflammatory
approaches the
alveolar bone
Osteoclastic bone
resorption
protective
mechanism to
prevent bacterial
invasion
leads to tooth
mobility and even
tooth loss.
The concentration of inflammatory
mediators
The inflammatory mediators must
penetrate to a critical distance of
the alveolar bone
Two critical
factors that
determine
whether
bone loss
occurs

57. References
 Del Fabbro, M., et al. "[Congenital neutrophil defects and
periodontal diseases]." Minerva stomatologica 49.6 (2000): 293-
311.
 Assuma, R., et al. "IL-1 and TNF antagonists inhibit the
inflammatory response and bone loss in experimental
periodontitis." The Journal of Immunology 160.1 (1998): 403-409.
 Tonetti MS, Imboden MA, Lang NP: Neutrophil migration into the
gingival sulcus is associated with transepithelial gradients of
interleukin-8 and ICAM-1. Perio ontol 69:1139 1147, 1998.
 Silva, T. A., et al. "Chemokines in oral inflammatory diseases: apical
periodontitis and periodontal disease." Journal of dental research
86.4 (2007): 306-319.
 Hajishengallis, George, et al. "Complement involvement in
periodontitis: molecular mechanisms and rational therapeutic
approaches." Immune Responses to Biosurfaces. Springer
International Publishing, 2015. 57-74.