Immunity and Host Defense against Oral Infections (complete) Flashcards
Which two things in the oral cavity acts as a physical barrier that prevents pathogen invasion
- the integrity of the Oral Mucosa
2. tooth enamel
What are the two types of immunity that you can find in the Oral cavity
Non-specific (innate) immunity
Specific (adaptive) immunity
Which type of immunity in the oral cavity is non-specific and continuous
innate or adaptive immunity
innate
What triggers the activation of adaptive immunity in the oral cavity
a response to specific pathogen/antigen which causes an antigen-specific antibody response or a T-cell response
What things come from gingival crevicular fluid that assist in immunity of the oral cavity
- Polymorphs (PMNs)
- Complement pathway proteins
- IgG
- IgA
What is the class, function and abundance of Neutrophils
Class = Granulocyte Function = Phagocyte, innate immunity Abundance = 62%
What is the class, function, and abundance of lymphocytes
Class = agranulocytes Function = adaptive immunity Abundance = 30%
What is the class, function, and abundance of monocytes
Class = agranulocytes Function = phagocytes (macrophages in the tissues) Abundance = 5%
What is the class, function and abundance of eosinophils
class = granulocyte function = removal or hemoliths and Ab/Ag complexes abundance = 2%
What is the class, function, and abundance of basophils/mast cells
class = granulocytes function = allergy response, inflammation abundance =
What are the different soluble mediators of immunity in the oral cavity
Antibodies
Complement components
Cytokines
what are the antibodies that are soluble mediators of immunity in the oral cavity
sIgA
IgM
IgG
What is the main complement component that is a mediator of immunity in the oral cavity
C3
what are the cytokines that are soluble mediators of immunity in the oral cavity
IL-1
IL-6
TNF-alpha
From where does sIgA come from
saliva
What are the 4 barriers of innate immunity in the oral cavity
- anatomic barriers
- physiologic barriers
- phagocytotic barriers
- inflammatory barriers
What makes up the anatomic barrier of the oral cavity
the epithelial cells of the oral cavity
What are the three ways that epithelial cells of the oral cavity fight infection
- act as a physical barrier
- the production of antibiotics, cytokines, and NO
- housing intraepithelial lymphocytes that kill the microbe
How do epithelial cells produce antibiotics, ctyokines, and NO
They have TLRs on their surface that recognize PAMPs, the binding of PAMPs by the TLRs signals epithelial cells to produce peptide antibiotics, cytokines, and NO
What are PAMPs
they are pathogen associated molecular patterns. (certain molecular patterns that are only found in pathogens)
What are TLRs
Toll-Like receptors (receptors on cell surfaces that recognize and bind to PAMPs)
What does TLR-2 bind to
Lipoteichoic acid that is found in gram + bacteria
what are two types of gram+bacteria that are bound by TLR-2
Actinomyces
Strep
What does TLR-4 bind to
lipopolysaccharides (LPS) of gram - bacteria
what is a type of gram - bacteria that TLR-4 binds
prevotella
Do oral cavity epithelial cells express receptors for sIgA
Yes
how does the swallowing of saliva affect immunity of the Oral cavity
it removes microbes from dental plaque and oral mucosa
How do pH and Temperature of the saliva affect immunity of the mouth
A rise in pH in gingivitis and periodontal disease favors putative periodontal pathogen growth
A rise in temperaure alters bacterial gene expression, and immune evasion
what is the normal pH in the mouth
6.9
What things found in saliva are antimicrobial in nature
lactoferrin lysozyme Myeloperoxidase system salivary peroxidase system antimicrobial peptides complement leukocytes sIgA
What is lactoferrin of saliva and what does it do in oral cavity immunity
an Iron binding molecule that is bacteriostatic (stops bacteria from reproducing)
What is lysozyme of saliva and what does it do in oral cavity immunity
it is a basic protein that breaks down bacterial structure
what bacteria is the lysozyme of saliva effective against
S. mutans
what is the Myeloperoxidase system of saliva and what does it do in oral cavity immunity
it is a bactericidal generating halide, H2O2 in PMNs migrate to the gingival crevice to start inflammatory response
What is the salivary peroxidase system of saliva and what does it do in oral cavity immunity
It is a bactericidal generating thiocyanate that produces H2O2
What are the main antimicrobial peptides that are found in saliva
histatins and defensins (alpha and beta)
they are small cationic peptides with antimicrobial activity
what are histatins and what do they do for oral cavity immunity
they are histidine rich peptides with broad anti-fungal and anti-bacterial activity
what are defensins and what do they do for oral cavity immunity
they have broad anti-fungal, bacterial and VIRAL activity
what to Beta defensins do specifically
protect mucosal surfaces
what does the complement from saliva do for oral cavity immunity
Breaks down C3 derived from GCF (gingival Crevicular fluid)
What do leukocytes from saliva do in oral cavity immunity
secrete alpha defensin
phagocytosis
microbial killing
what happens to leukocyte activiy in the oral cavity with inflammation
it increases
What is sIgA from saliva and what does it do in oral cavity immunity
it is the major Ab in saliva and it inhibits microbial adherence, agglutinates bacteria, and neutralizes viruses
What is the phagocytic barrier involved in immunity of the oral cavity
the presence of phagocytes that destroy pathogens
how do phagocytes destroy pathogens
- they bind the pathogen using cell surface receptors
- engulf the pathogen in a phagosome
- pump in toxic reactive oxygen and nitrogen intermediates to kill the pathogen
What are the oxygen-independent methods phagocytes use to kill pathogens
Lysozyme
Defensins
Lactoferrin
Proteolytic and hydrolytic enzymes
what does lysozyme do
breaks down cell wall components
what are the oxygen dependent methods phagocytes use to kill pathogens
Hydrogen peroxide superoxide anion hydroxyl radical myeloperoxidase hypochlorite hypohalite Nitric oxide
what is CGD
chronic granulomatus disorder, a disorder where phagocytes lose their ability to completely eliminate engulfed pathogens.
what are the treatments for CGD
antibiotics (high dose, long term)
IFN-y injections to activate macrophages
what Abs does the Gingival crevicular fluid have
IgG, IgA, and IgM
saliva has sIgA
What are some key characteristics of IgG
- monomer
- 70% of total Ab
- crosses the placenta and protects fetus
- activates complement
- major opsonizing Ab
- protects gingiva and gingival portion of crown
What are some key characteristics of IgM
- Pentamer
- 10% of total Ab
- first Ab generated against any Ag
- predominant Ab produced by the fetus
- Ab for carb antigens (ABO)
- protects gingiva and gingival portion of the crown
What are some key characteristics of IgA
- in serum as monomer, in secretions as dimer
- lines the oral cavity and doesn’t allow pathogens to adhere
- mucosal immunity
- sIga distinguishes between commensals and pathogenic molecules
what is immune exclusion
the ability of antibodies (sIgA) to tell between commensal and pathogenic molecules
what mediates humoral mucosal immunity
sIgA
there are two classes of IgA. IgA-1 and IgA-2. what is the difference
IgA-1 is more concentrated in plasma (both equal in saliva)
IgA-1 is directed against protein antigens
IgA-2 is directed against carb antigens
what does the M-cell of the mucosal immune system do
captures the Ag and delivers it to DCs. this signals IELs to migrate to mesenteric lymph nodes
what is the main difference between oral and gut mucosal immunity
gut has MALT mouth has Oral lymphoid foci
what are the two main immunologic functions of the mucosal epithelium
- provides physical barrier between the body and microbes
2. confers the first line of immune defense against the microbes
what type of T-cells are most IEL’s (intraepithelial lymphocytes)
CD8+
what do DC (dendritic cells) do in oral mucosa
sample between epithelial cells for Ags
what are the three functions of the oral mucosal immune system
- respond to harmful organisms
- regulate influx of immune cells
- prevent inflammatory tissue destruction
what happens to commensal bacteria if the homeostasis between them and the mucosal immune system becomes unbalanced
they become surrogate pathogens and stimulate a chronic inflammatory response
what does dental plaque at the gingival margin result in
acute inflammation
what does acute inflammation do to GCF
it increases the flow of GCF
an ecological imbalance between the endogenous flora and host immune response results in
dental caries and periodontal disease
what causes dental caries
frequent consumption of fermentable carbs. which is used by S. mutans and that gives off acid which degrades enamel
what do M-cells do the the mouth
they capture antigens and deliver them to Dendritic cells, those then cause the secretion of IgA
what do mucosal epithelial cells secrete as a non-specific shield to prevent microbe damage
mucins defensins trefoil peptides acquired enamel pellicle lysozyme NO