The document summarizes the defensive mechanisms of gingiva. It discusses four key components: the epithelial surface, gingival crevicular fluid, the initial stages of inflammatory response, and saliva. Regarding the epithelial surface, it describes the junctional epithelium and its role in forming a protective barrier against plaque bacteria while allowing access of immune cells and components. It also notes enzymes and antimicrobial substances produced by junctional epithelial cells. The document then reviews the composition and functions of gingival crevicular fluid, including its role in flushing out bacteria and transporting antibodies and immune cells. It lists several enzymes found in gingival crevicular fluid and their sources and functions. Finally, it briefly mentions

1. DR JEEVANAND DESHMUKH
PROFESSOR AND HEAD
DEPARTMENT OF PERIODONTOLOGY
NAVODAYA DENTAL COLLEGE AND HOSPITAL

2. Introduction
• The teeth, the gingival masticatory mucosa,
create a unique environmental challenge
to the protective continuity of gingiva.
• At the interface where the healthy gingiva
meets the tooth surface the structural
continuity is secured by the epithelium .

3. • At the dentogingival junction the micro-organisms form complex
on solid and non-
ecological systems that adhere to glycoprotein layer
shedding surfaces and are called as biofilms.
• Since a biofilm is quickly formed on exposed tooth surfaces, the tissue in
the vicinity of this biofilm is constantly challenged.
• Such aggravating external circumstances call for a specialized structural
and functional adaptation for the defence mechanism of gingiva.

4. • Apart from bacterial aggressions gingiva is constantly subjected to
mechanical agressions as well.
through the fine tuning of
• Thus gingiva prepares and protects itself
homeostasis. (Kornman W)
• Defence mechanism of gingiva includes four vital components
• epithelial surface
• gingival crevicular fluid
• the initial stages of inflammatory response and
• saliva

5. EPITHELIUM
• Epithelia -first line of defence
• It exhibit considerable differences in histology, thickness and
differentiation suitable for the functional demands of their location.
• The epithelial component of gingiva shows morphologic variations as oral
epithelium, sulcular epithelium and junctional epithelium

6. Possible protective role of the oral epithelium
• An intact epithelial barrier of the gingival, sulcular, and junctional
epithelia under normal conditions is an effective barrier against penetration
of bacterial components and metabolites.
• There is a high turnover rate
replacement of cells and tissue components that are damaged by the
microbial challenge.
removal of bacteria that have colonized the cellular surface and
regeneration of an intact epithelial barrier.
In addition, cells of the oral epithelium contain lysosomes and can exhibit
limited phagocytic activity.

7. • Junctional epithelium (JE) consists of active populations of cells and
antimicrobial functions, which together form the first line of defense
against microbial invasion into tissue .
III.
• Exhibits several unique structural and functional features-:
I. Rapid cell divison
II. Funnelling of JE towards the sulcus (contributes to the flow of epithelial
cells (Schroeder HE,1979) )
Internal basal lamina an effective barrier (laminin)
IV. Anti microbial substance by JE cells. (ICAM 1, defensins)
V. Cytokines (IL-8, IL 1 α,IL 1β,TNF )
(Bartold, 2000)

8. i. Contains proteolytic enzymes- Matrix metalloproteinases(MMP)
(Salonen J, 1991).
• Gelatinase B (MMP-9) is one of the most abundant MMPs- degrade type
IV collagen.
• Collagenase-3 (MMP-13) - collagenase-3 degrades collagens type I, III and
IV as well as fibronectin and some proteoglycan this enzyme seems to play
an important role in invasion of periodontal connective tissue.
• Gelatinase A (MMP-2)- in inflamed pocket epithelium and to be important
in epithelial cell migration (Mäkelä M,1991).

9. • Matrilysin (MMP-7) is another epithelial MMP with a broad spectrum of
substrates. It can degrade fibronectin, laminin, type IV collagen, gelatin and
proteoglycan core proteins.
• Matrilysin is expressed only in the suprabasal cells of JE facing the teeth
and in epithelial cell rests of Malassez.
ii. Other serine proteinases include
 Lysosomal cysteine
 aspartic acid proteinases
 Cathepsin D.
 Cathepsin C (dipeptidyl aminopeptidase) is an enzyme important in the
intracellular degradation of proteins and activation of serine proteinases
critical to inflammatory responses.

10. iii. Tissue plasminogen activator (t-PA) (Schmid et al.,1991) and its inhibitor
Plasminogen activator inhibitor (Lindberg et al., 2001) have been
detected in the junctional epithelium.
• Tissue plasminogen activator and urokinase is a serine protease which
converts plasminogen to plasmin.
• Plasmin degrades many extracellular matrix proteins and activates many
matrix metalloproteinases (MMPs)-collagenases and mediators of
complement system.

11. iv. Enzyme-rich lysosomes.-Lysosomal bodies are found in large numbers in
the JE, containing enzymes which participate in the eradication of the
bacteria (Langer and Schroeder, 1971).
eg. cysteine proteinases (cathepsin B and H)
neutral proteinases
chymotrypsin-like proteinase . (cathepsinA)
v. Antigen presenting cells, langerhans cells and dendritic cells are also
present(Juhl et al., 1988)

12. • PMNs - central region of the JE and near the tooth surface, intercellular
spaces.
• lymphocytes and macrophages in and near the basal cell layer
• mononuclear leukocytes in intercellular spaces.
vi. The fluid filled intercellular spaces may vary in width, but are wider in
comparison to oral gingival and sulcular epithelium (Schroeder 1970)-
remarkable permeability.

13. • The intercellular spaces of the junctional epithelium provide a pathway for
fluid and transmitting leukocytes. .. represent a host defence system against
the bacterial challenge.
• These spaces are approximately 2–5% of the junctional epithelial volume in
normal conditions and are infiltrated by small numbers of neutrophils,
mononuclear cells and lymphocytes.
• However, during periods of inflammation, these intracellular spaces are
found to contain abundant migrating leukocytes.

14. • In addition, the large intercellular spaces of the junctional epithelium can
be distended and act as reservoirs for the GCF.
• This can prevent the penetration of bacteria into the epithelium and can act
as a diffusion barrier.
• It also functions as a diffusion pathway for the GCF and its components –
such as chemotactic agents, antibodies, complement components and other
host-derived enzymes, and provides them with an entry into sulcus.
• However, under periods of prolonged exposure to bacterial plaque and the
amplification of the inflammatory response, the protective function of the
junctional epithelium starts to erode and the large intercellular spaces allow
the passage of bacteria and their by-products into the host tissues.

15. To summarize
• Junctional epithelium is firmly attached to tooth surface forming an epithelial
barrier against plaque bacteria.
• It allows access of gingival fluid, inflammatory cells and components of
immunologic host defense to gingival margin.
• Cells exhibit rapid turnover, which contributes to host-parasite equilibrium and
rapid repair of damaged tissue.
• Also cells of junctional epithelium have an endocytic capacity equal to that of
macrophages and neutrophils, and this activity may be protective in nature.
(Cho MI, 2000)

16. GCF
• “GCF is an exudate of varying composition found in the sulcus/periodontal
pocket between the tooth and marginal gingiva.”
(Cimasoni G (1983), Embery G(1994))

17. • The studies of Brill ,1958, 1959,1969 postulated that
 GCF was an important component of the protective mechanisms of the
crevicular region.
 This concept was supported by the flushing effect of GCF
 The important role that GCF may have in transporting antibacterial
substances, either of host origin or those introduced into the circulation
such as antibiotics, to the crevicular space was appreciated.
 He concluded that stimulation of the gingival margin was important for the
maintenance of gingival health.

18. Composition of GCF
Cells bacteria, Epithelial cells,
Leukocytes
electrolytes calcium, sodium, flouride,
magnesium, phosphate, potassium
Host tissue complement, fibrin , fibronectin,
collagens, osteocalcin, osteonectin ,
proteoglycans
microbial products bacterial enzymes, cytotoxic
substances, metabolic end products,
lipopolysaccharides

19. Enzymes and other compounds reported in the GCF
• Acid phosphatase
• Alkaline phosphatase
• α 1 antitrypsin
• α 2 macroglobulin
• Aryl sulfatase
• Aspartate aminotransferase
• ß glucuronidase
• Chondroitin sulfatase
• Citric acid
• Cytokines (IL-α, IL-β, IL-6, IL-8,
• Immunoglobulins (IgG, IgA, IgM)
• Cystatins
• Exopeptidases
• Endopeptidases
• Cathepsin
• Elastase
• Collagenase
• Tryptase-like
• Trypsin-like
• Glycosidase
• Sialidase
• Galactosidase
• Mannosidase

20. Compounds & enzymes of bacterial origin detected in GCF
• Acid phosphatase
• Alkaline phosphatase
• PhospholipaseA
• Phospholipase C
• Lysophospholipase
• Aminopeptidases
• Betalactamases
• Collagenase
• Chondroitin sulfatase
• Aminopeptidases
• Chymotrypsin-like
• Trypsin-like
• DNase
• Fibrinolysin
• Glucosidases
• Hemolysin
• Hyaluronidase
• Iminopeptidases
• Immunoglobulinases

21. Alkaline phosphatase
• ALP is a calcium- and phosphate-binding protein and a phosphor-
hydrolytic enzyme. (Bezerra AA, 2010)
• It is a membrane-bound glycoprotein produced by many cells such as
polymorphonuclear leukocytes (PMNLs), osteoblasts, macrophages, and
fibroblasts within the area of the periodontium and gingival crevice.
• This intracellular enzymes are released increasingly from the injured,
damaged cells or dead cells of periodontal tissues into the gingival
crevicular fluid (GCF) and saliva.
(Daltaban O,2006)

22. • Could also be released from bacterial cells.
• ALP is considered to be an important indicator of bone formation and is a
phenotypic marker for osteoblast cells.
• The pH optimum for alkaline phosphatase activity is 9.0. (Mobley DN,
1984)

23. Acid phosphatase
• Acid phosphatase a lysosomal enzyme, used to free attached phosphoryl
groups from other molecules seein in polymorphonuclear leukocytes (PMNLs),
fibroblasts and has high activity in bone resorbing cells such as Osteoclast and
macrophages. (Yajima, 1986)
• Acid phosphatase is stored in lysosomes and functions when these fuse
with endosomes, which are acidified while they function; therefore, it has an
acid pH optimum. (Henneberry, 1969).
• Seen in Odland bodies.
• The pH optimum for acid phosphatase activity is 4.8-5.8. (Mobley DN, 1984)

24. Cathepsin
• It Is a serine endopeptidase contained in the azurophil granules of human
PMNs.
• Also called chymotrypsin like, because it attacks a number of synthetic
substrates typical for chymotrypsin and is inhibited by the same inhibitors.
• It has an optimum pH of 7.5 and a molecular weight of about 20,000.
• This Enzyme has been shown to hydrolyze hemoglobin and fibrinogen,
casein and collagen. (Starkey PM, 1976)

25. Elastase
• Elastase is a serine endopeptidase that can degrade both collagneous and
non collagenous extra cellular matrix proteins.
• It is released at sites of inflammation.
• The levels of this enzyme in GCF have been noted to increased with
development of gingivitis as well at sites of established periodontitis.
• In addition, the levels of neutrophil elastase have been found to decrease
following treatment of affected periodontal sites. (Meyle J, 1992)
• Longitudinal studies have indicated that GCF levels of neutrophil elastase
have some of further breakdown.

26. Cellular Elements
• Cellular elements found in GCF include
-Bacteria : Despite having constitution similar to the neighbouring plaque,
do not increase with
the actual number of bacteria isolated from GCF
increasing plaqueaccumulation.
- Desquamated epithelial cells
- Erythrocytes
- Leukocytes

27. Leukocytes
• Leukocytes are detected in both clinically healthy and diseased tissues.
(Attstrom et al., 1970).
• In 1960, Sharry & Krasse determined -
-47% of all cells obtained from the gingival sulcus were leukocyte
-major route of entry into the oral cavity was via the gingival sulcus.

28. • PMN cells are found in the
-intercellular spaces of JE
-along the tooth surface -Adjacent to plaque
-base of the sulcus > coronally
• Attström et al, 1970 - one of the first study (gingival sulcus)
• Differential count of 95–97% neutrophils
1–2% lymphocytes
2–3% macrophages cells.

29. • Wilton et al.
that of 8.8%
1976 focused predominately on the populations of
of total mononuclear
leukocytes, and established
18% - macrophages
24% were T lymphocytes
58% were B lymphocytes.
T-cell : B-cell ratio of 1: 2.7 ( opposite situation peripheral blood)
• Localization + persistent emigration-chemotactic factors
bacteria, host-derived chemotactic factors

30. • Under inflamed conditions, 60% or more of the JE space can be occupied
by neutrophils.
• Initial explanations for the elevation of PMN cell counts in the presence of
inflammation α sulcular fluid flow.
• However, 2.1-fold increase of neutrophils the GCF flow increased almost
5.5-fold during the same period ( Kowashi et al, 1980). It was concluded-
both are two distinct phenomena & migration of inflammatory cells is
directed along gradients of chemoattractants

31. along the
• Once in the sulcus, PMNs begin to create a ‘leukocyte wall’
margins of plaque mass.
• kinetics of leukocytic emigration (Attström & Egelberg, 1970)
radiolabeled PMNs
-appeared in the gingival sulcus 20–30min after being present in the blood
- a peak neutrophil concentration within the sulcus after 1h.

32. • crevicular PMNs are capable of phagocytosis + extracellular killing of
pathogens(‘suicidal’action). (Scully ,1982)
• Reports identifying possible defects in gingival crevicular PMNs,
- decreased responsiveness to chemotactic substances
- loss of the ability to adhere or migrate
- and reductions in phagocyte activity and intracellular killing
(Miyazaki 1997)

33. • Major events in leukocyte lifecycle
 Generation of acute phase signals- C5a
 Migration –chemoattaractants factors
 Phagocytosis of microbial invaders
 Killing of bacteria

34. The potent enzymatic in PMNs act as ‘double-edge sword’, functioning to
protect the host from microbial invaders but also contributing to the host tissue
destruction.

35. • Three potent enzymes that affect the tissues of the periodontium are
collagenase, elastase, and gelatinase.
• In addition, crevicular PMNs are capable of producing pro-inflammatory
mediators directly.
• Other Cellular components-
Macrophages (2–3%) -Phagocytes
-APC
-Enhance the
antimicrobial actions
of PMNs.
-sources of pro-
inflammatory
cytokines.
T lymphocytes Humoral
B lymphocytes
1–2%
plasma cells.

36. Electrolytes in GCF
• Potassium, sodium, and calcium have been studied in GCF. Most studies
have shown a positive correlation of calcium and sodium concentrations
and the sodium-to-potassium ratio with inflammation.
(Kaslick RS, Mandel ID, Chasens AJ, 1970)

37. Organic Compounds in GCF
• Both carbohydrates and proteins have been investigated.
• Glucose hexosamine and hexuronic acid are two of the compounds found
in GCF.
• Blood glucose levels do not correlate with GCF glucose levels; glucose
concentration in GCF is 3-4 times greater in serum due to
- metabolic activity of adjacent tissues,
- local microbial flora.
(Hara K et al., 1969)
• The total protein content of GCF is much less than that of serum. No
significant correlations have been found between the concentration of
proteins in GCF and the severity of gingivitis, pocket depth, or extent of
bone loss.
(Solis Gaffar MC et al., 1980)

38. Proteolytic host cell enzymes in GCF
lipids and
• A variety of enzymes that degrade proteins, proteoglycans,
carbohydrates have been detected in GCF.
• Enzymes, especially proteinases that have a role in periodontal tissue turnover
in health and in the tissue destruction that characterizes diseases of the
periodontium.
• Serine proteinases
• Matrix metalloproteins
•Cysteine &Aspartic proteinases
(These are the enzymes of neutrophils)

39. • Under normal conditions, there is a balance between the amount/activity of
proteolytic enzymes and enzyme inhibitors, thereby keeping the activity of
the secreted enzymes under control. In highly inflamed sites, tissues are
infiltrated with neutrophils and other proteinase-producing inflammatory
cells.

40. • Serine proteinases
Elastase
fibronectin, laminin 1,
Proteoglycans
Fibronectin and type IV
(neutrophil transmigration)
Extensive degradation of
extracellular matrix
Elastase and cathepsin G are
capable of activating
epithelial cells to produce IL-
8, IL-6 and prostaglandin E2
Cathepsin G convert the inactive
angiotensin I to angiotensin II.
regulate vascular permeability
and monocyte chemotaxis
Proteinase-3 collagen type IV, elastin,
vitronectin

41. plasminogen activator large substrate specificity.
Plasmin plays a pivotal role in
fibrinolysis.
degrades extracellular matrix
proteins
activates complement .
convert latent pro-matrix
metalloproteinases into active forms
.

42. Matrix metalloproteins
(GCF and saliva)
collagenase (MMP-8) interstitial collagens,
Leukocyte Collagen types I,
II, III, VII, X
Gelatinase (MMP-9) Gelatinolytic enzyme
degrading several
extracellular matrix
proteins, including
basement
membrane (type IV)
gelatin
fibronectin, vitronectin,
laminin, elastin, aggrecan
MMPS

43. Cysteine & Aspartic proteinases
Cysteine proteinases (Cathepsin S,
L, B, H)
Elastin,
several denatured proteins,
activation of pro-MMPs
prourokinase
Aspartic proteinases (Cathepsin D,
E
Proteoglycans,
several denatured proteins

44. • Enzyme Inhibitors
 Specific inhibitors, called serpins, restrict the serine proteinase activity in
tissues.
 Both uPAand plasmin have their own specific inhibitors, uPA-inhibitor and
plasmin inhibitor.
 TIMPs
 Cystatins

45. • Epithelial cell proteinases
i. Matrix metalloproteinases
ii. Other serine proteinases.
iii. aspartic acid proteinases
iv. Tissue plasminogen activator (t-PA) (Schmid et.al.,1991) and its inhibitor
PA1-2

46. • Fibroblast proteinases
Fibroblasts are largely responsible for the turnover of connective tissue in
normally functioning tissues such as gingiva and periodontal ligament.
MMP s
MMP-1 (collagenase-1)
MMP-2 (gelatinase A)
MMP-3 (stromelysin-1)
MMP-13 (collagenase-13)
MT1-MMP (MMP-14).
degrade all the components
of connective tissue, including
different collagen types,
adhesion proteins and
proteoglycans
Serine Proteinases.
Cysteine Proteinases.
Cathepsins B And L
intracellular collagen
degradation of fibroblasts
Aspartic Acid Proteinases.
t-PA

47. collagen-degrading enzymes P. gingivalis,
A.actinomycetemcomitans and
spirochaetes
elastase-like enzyme spirochaetes and Capnocytophaga
species
trypsin-like proteases P. gingivalis, B. forsythus,
T. denticola and other spirochaetes
Chymotrypsin like enzymes
T. denticola and Capnocytophaga
species
aminopeptidases Capnocytophaga species and T.
denticola
dipeptidylpeptidases P. gingivalis, P. intermedia and
Capnocytophaga species

48. Hyaluronidase and
chondroitinase
activities
These could hydrolyze the
GAG
components of
proteoglycans in the ECM
by C. ochracea, F.
nucleatum, P. gingivalis
and T. denticola
Neuraminidase
(sialidase) activity
might attack sialoproteins
in the
epithelium, thereby
increasing its permeability
to
bacterial products
B. forsythus, Prevotella
melaninogenica and
P. gingivalis
phospholipases Damage to the surface of
epithelial
and other cells
Porphyromonas, Prevotella
and
Bacteroides species
acid and
alkaline phosphatase
Porphyromonas,
Prevotella, Bacteroides and
Capnocytophaga
species

49. Products of inflammation in GCF
• Lysozyme
 Lysozyme is an enzyme found in tears, nasal, and gastric secretions saliva
and GCF.
 It is present in both the basic and azurophil granules of PMNs and cleaves
the £-1-4 glycosidic bonds of bacterial cell wall peptidoglycans and
features as a bactericidal agent.
 Levels differ b/w gingivitis and periodontitis sites. ( Modeer and Twetman
1979)

50. Lactoferrin
• This is an antimicrobial agent with a distribution in PMNs and secretory fluids
similar to that of lysozyme.
• The antibacterial properties- due to its high affinity for iron, thus locking
available sources required for bacterial growth.
GCF in sites showing gingivitis and
• Lactoferrin increased twofold in
periodontitis. ( Friedman et al.,1983)
• It has also been reported that the ratio of lactoferrin to lysozyme may be more
representative and a useful diagnostic assay of periodontal inflammation.

51. Cytokines in GCF
IL-1 Armitage ,1996
IL-2.
IL-6
Cox, 1986
Geivelis et al., 1990
IL-8 Payne et al, 1998
TNF-a Beutler and Cerami, 1990

52. Acute Phase Proteins
α – 2- Macroglobulin
α 1-anti-trypsin
Transferrin
Haptoglobulin
CRP
Adonogianaki et al., 1992

53. • Eicosanoids: Prostaglandins and Leukotrienes-Prostaglandin E2 (PGE2)
has been found in elevated quantities in GCF.
• GCF levels increases 2- and 3- fold in inflammation and 5- to 6-fold
during periods of active attachment loss and bone resorption. (Offenbacher
et al.,1991)
• LTB4 is elevated in inflamed deeper periodontal tissues.

54. • Immunoglobulins in GCF-Immunoglobulins and antibodies of all isotypes
are generally at low levels in GCF from healthy sites. (Reinhardt et al.
1989)
• GCF IgG1 and IgG4 were significantly elevated in active when compared
to stable sites in periodontitis patients and that both were elevated relative
to serum.

55. Complement activation in GCF
• Numerous complement components have been reported in GCF, derived
from serum and/or local synthesis.
• Healthy gingival sulcus GCF fluid transudate contains both C3 and C4.
• Cleaved C3 is increased in GCF at gingivitis sites .
• chronic periodontitis -Only C3 is activated
• Aggressive Periodontitis - C4a, C3b and C5a ( both pathways)
• Significant amounts of bone-resorbing IL-6 are released by osteoblast-like
cells stimulated by C5a. (Pobanz JM etal 2000).

56. Growth Factors
• Regulate key cellular events in tissue repair, including cell proliferation,
chemotaxis, differentiation, and matrix synthesis
EGF- No significant differences in EGF concentrations were found between
the periodontal disease and control groups
TGF-a significant correlations were found between GCF TGF-a
concentrations and pocket depth measurements, bleeding on probing, and
radiographic bone loss.
(Mogi et al.,1994)
PDGF – (Salcetti et al 1997).
VEGF -(Deckers MM 2000).

57. SALIVA
• Whole saliva is an important physiologic fluid that contains a highly
complex mixture of substances.
• It is secreted primarily by three paired major salivary glands and
secondarily by hundreds of minor salivary glands located below the
mucosal surfaces of the mouth.
• Salivary gland secretions contain locally produced proteins, as well as other
molecules from the systemic circulation.

58. Composition of saliva
• SALIVA -WATER (99.5%) and SOLIDS (0.5%).
• Solids include ORGANIC (0.3%) and INORGANIC (0.2%).
• organic constituents include ptaylin, kallikrein, bradikynin, lysosome ,
immunoglobulin igg, mucin, blood group antigen, nerve growth factor, vit c
and vit k, urea and uric acid, cellular components and gama globulin.
• inorganic constituents include- sodium, chlorine, potassium, calcium,
phosphate, fluoride, magnessium, bicarbonate and thiocynate.

59. • Enzymes in saliva
 Derived from the salivary glands, bacteria, leukocytes, oral tissue and
ingested substances; the major enzyme is parotid amylase.
 S.E. increased in concentration in periodontal disease are hyaluronidase,
lipase, B-glucuronidase and chondritin sulfatase, amino acid
decarboxylases, catalase, peroxidase and collagenase.

60. • Proteolytic enzymes generated by both host and bacteria. They have been
recognised as contributors to the initiation and progression of periodontal
disease, to combat these enzymes; saliva contains antiproteases that inhibit
cysteine proteases such as cathepsins and anti-leucoproteases that inhibit
elastase.
• Another antiprotease identified as a tissue inhibitor of matrix metalloprotienase
(TIMP) has been shown to inhibit the activity of collagen – degrading enzyme

61. • Antibacterial factor-Saliva contains inorganic and organic factors that
influence bacteria and their products in the oral environment.
• Inorganic factors includes ions and gases, bicarbonate, sodium,
potassium, phosphate, calcium, fluorides, ammonium, and carbon dioxide
• Organic factors include lysozyme, lactoferrin, myeloperoxidase, lacto
peroxidase and agglutinins such as glycoproteins, mucins, Beta-2
macroglobulins, fibronectin, and antibodies.

62. • Lysozyme
• Is a hydrolytic enzyme that cleaves the linkage between structural
components of the glycopeptide (muramic acid)
– found in the cell wall of certain bacteria’s.
• Lysozyme works on gram negative and gram-positive organisms,
Veillonella species andA.A. are some of their targets .
• It probably repels certain transient bacterial invaders of the mouth (Pullock
et al 1985).

63. • The lactoperoxidase-thiocynate system in saliva-Is bactericidal to certain
strains of lactobacillus and streptococcus by preventing the accumulation of
lysin and glutamic acid, both of which are essential for bacterial growth.
• Lactoferrin is effective againstActinobacillus species (Arnold et al 1980).
• Myeloperoxidase -An enzyme similar to salivary peroxidase is released
by leukocytes and is bactericidal for actinobacillus, but has added effect of
inhibiting the attachment ofActinomyces strain to hydroxyapatite.

64. Vitamins
• They are found in saliva, as thiamine, riboflavin, niacin, pyridoxine,
pantothenic acid, biotin, folic acid and vitamin C and B12, and vitamin K
are also reported. Suggested sources of the oil are microbial synthesis and
secretion by salivary gland, food debris, degenerating leukocytes and
exfoliated epithelial cells.
Coagulation factors
• Saliva also contains coagulation factors VIII, XI, X, plasma thromboplastin
antecedent (PTA) and the Hageman factor that hasten blood coagulation
and protect the wounds from bacterial invasion. Presence of an active
fibrinolytic enzyme has also been suggested.

65. • Bacteria
• Bacteria in general and specific species in particular are important in the
etiology of gingivitis and periodontitis(Socransky.1970,Genco et al
1988).Further more detection of certain species in saliva can reflect their
presence in periodontal pockets (Asikainen et al.1991,Umeda et al.1998) Saliva
has also been suggested as an important vector in bacterial transmission
(Greenstein &lamster.1997.therefore analysis of saliva may prove to be an
important approach for detection of pathogenic oral bacteria , and may replace
other more complicated and more invasive sampling methods.
•

66. • Blood group active glycoproteins: mucins and salivary agglutinin two
genetically distinct mucin types, designated MG1 and MG2 (Levine et al,
1987)
• MG1, which displays blood group activity, exists in at least three different
glycoforms, differing in sialic acid and sulphate content, depending on the
glandular source (Veerman et al, 1992).
• MG2 has been found to exist as at least two glycoforms, MG2a and MG2b.
the secretory mucins form hydrophilic viscoelastic gels.

67. • These gels function as barriers, protecting the underlying epithelium against
mechanical damage and preventing direct entrance of noxious agents, including
bacteria and viruses, into the underlying vulnerable epithelium.
• Agglutinin
 Salivary agglutinin is a highly glycosylated protein, with a molecular mass of
approximately 340 kDa, that carries blood group active antigen.
 Salivary agglutinins are expressed in the serous cells of the submandibular,
sublingual and labial glands (Sharma et al., 1998).

68. • Agglutinin is also synthesized in the serous parotid gland.
• Agglutinin binds to a wide variety of microorganisms, including S. mutans,
S. salivarius and S. sanguis (Ligtenberg et al., 2000),resulting in enhanced
phagocytosis and killing of microorganisms by neutrophils and macro-
phages (Holmskov et al., 1999)

69. Cystatins
• cysteine proteinase inhibitory activity (Shomers et al, 1982).
• Because of their proteinase inhibiting properties, cystatins have been
suggested to play a role in controlling proteolytic activity, either from the
host (released during inflammatory processes) or from microorganisms.
• Cystatin S can inhibit partially proteolytic enzymes released in P. gingivalis
culture medium (Blankenvoorde et al.,1996).

70. Von Ebner glands protein (VEGh)
• VEGh is a salivary protein secreted by the Von Ebner glands located around
the circumvallate and foliate papillae of the tongue.
• Originally it has been assumed that VEGh was involved in the perception of
bitter taste.
• However, later it was demonstrated that VEGh can act as inhibitor of cysteine
proteinases (Van't Hof et al., 1997).
• Evidence has also been produced that VEGh can act as an oxidative-stress
induced scavenger of peroxidation products (Redl et al., 1999)
• The ubiquitous presence of VEGh in various secretions, including saliva, tears
and semen, would indeed favour a more general role, e.g. as an antiviral agent.

71. secretory leucocyte proteinase inhibitor (SLPI)
• Another example of salivary protein with more than one function is the
Secretory Leukocyte Proteinase Inhibitor (SLPI).
• This protein is an inhibitor of serine proteinases (designated a serpin),
including neutrophil elastase, chymotrypsin and Cathepsin G.
• In addition to its proteinase inhibitory properties, SLPI has antimicrobial
and antiviral properties.

72. TIMPS: tissue inhibitors of metalloproteinases
• In parotid and submandibular secretions TIMP-1 has been identified, a member
of the family of tissue inhibitors of matrix metalloproteinases (MMPs)
• Considering their potent inhibitory action against MMPs, including
collagenase, gelatinase and stromelysin, TIMPs are thought to play an
important role in turnover and remodelling of the extracellular matrix.
• other unique functions of TIMPs have been reported, including erythroid
potentiating activity, cell growth-promoting activity, and stimulation of
osteoclastic bone resorption (Murate and Hayakawa 1999).
• Interestingly, the latter activity could not be ascribed to merely their inhibitory
effect on matrix proteolysis,indicating that TIMPs, like VEGh and SLPI, are
multifunctional proteins.

73. Extra-parotid glycoprotein (EP-GP)
• EP-GP is another example of a protein that originally had been implicated
in the formation of the dental pellicle, because of its high affinity for
hydroxyapatite (Rathman et al., 1989).
• The ubiquitous presence in mucosal secretions pointed to a more general
protective role for EP-GP, a concept that was supported by the observation
that this protein binds to microorganisms (Schenkels et al.,1997) as well as
to the CD4 receptor on monocytes(Autiero et al., 1997; Gaubin et al.,
1999).

74. Chromogranin A
cells and
• Chromogranin A is a major protein in adrenal chroma
f•
fin
adrenergic neurons.
• In humans, a prompt elevation of salivary chromogranin A-like
immunoreactivity is found in psychosomatic stresses (Nakane et al., 1998).
• Vasostatin-1, the natural N-terminal chromogranin A-derived fragment in
bovine sequence, displays antibacterial activity against Gram-positive
bacteria at micromolar concentrations and is also able to kill a large variety
of filamentous fungi and yeast cells (Lugardon et al., 2000).