Which of the following is the main microbial species is associated with early childhood caries?
Strep Mutans
Which of the following statement(s) is/are NOT correct for lymphoid tissues and organs?
B) T cell selection takes place in bone marrow
Which of the following is/are NOT among the soluble components of the acquired immune system?
B) Defensins
Which one is/are TRUE for the relationship between cariogenic plaque and pH?
a) All cariogenic plaques have pH lowering potential
b) Number of organisms correlate with plaque pH
c) Higher pH creates a favorable environment for mutans streptococci
d) There is a significant association between microbial composition and pH
a) All cariogenic plaques have pH lowering potential
b) Number of organisms correlate with plaque pH
Secondary lymphoid organs are where the antigens are trapped and presented to lymphocytes
True or False
True
Which of the following microbial species is/are associated with advanced periodontitis?
C) Porphyromonas gingivalis
Which of the following pathological state(s) do/does NOT involve an immunological process?
B) Dental erosion
Pattern recognition receptors (PRRs) are receptors on phagocytes that bind to pathogen-associated molecular patterns (PAMPs). Toll-like receptors (TLRs) represent one type of PRRs.
A) First statement is true; Second statement is true
Collectively, approximately how many bacterial species are there in the human oral cavity?
700
Which of the following statement(s) is/are correct?
a) Innate immunity is more evolved than the adaptive immunity
b) Adaptive immunity is specific but does not include memory
c) Innate immunity includes natural mechanisms that exist before infection
d) Rapid and early response to infectious agents can only be mounted through adaptive immunity
b) Adaptive immunity is specific but does not include memory
c) Innate immunity includes natural mechanisms that exist before infection
Which of the following is/are an IDEAL outcome of periodontal inflammation?
C) Resolution
Mammals only have acquired immunity capabilities
True or False
False
Which of the following is/are NOT a part of the ecological plaque hypothesis that explains caries?
A) Involvement of Porphyromonas gingivalis
Which of the following is/are NOT among the modified Koch’s postulates?
B) Direct causation
Which of the following is/are involved in periodontal disease pathogenesis?
a) Bacteria
b) Hypoxia in the periodontal pocket
c) cytokines
d) T cells
a) Bacteria
b) Hypoxia in the periodontal pocket
Natural Killer cells differentiate from myeloid lineage and are involved in acquired cellular immunity
True or False
False
Which of the following statement(s) is/are correct for lymphoid cells, tissues and organs?
A) Each individual lymphocyte matures bearing a unique variant of an antigen receptor.
Which of the following is/are correct for the complement system?
C) Complement system consists of a plasma protein cascade that can be initiated by three pathways called the classic, alternative and mannose-binding lectin pathways.
d) Natural killer cells use the complement system to opsonize and present antigens
Which of the following is/are TRUE for TLR recognition?
D) TLR4 activation is stimulated by LPS
Which of the following statement(s) is/are correct?
a) Porphyromonas gingivalis is a putative periodontal pathogen
b) Periodontitis results from plaque accumulation, regardless of the species present
c) Noma is a microbial infection that results in facial gangrene in malnourished children
d) Viruses have been implicated in periodontal diseases
A and C
All of the celular elements in blood arise from
Hematopoetic stem cells in marrow bone
B-lymphocytes, T-lymphocytes and Natural killer cells NK arise from
B cells, T cells, Neutrophils, Macrophages, Dendritic cells, mast cells, Eosinophils and basophils
Granulocyte-monocyte CFU gives rise to
Neutrophils and Monocytes
Characteristics of innate immune system?
Antigen non-specific
Rapid response (minutes)
no memory
Characteristics of adaptive immune system
Antigen specific
Slow response
Memory
Components of innate immune system
Natural barriers (skin, mucosa)
Phagocytes
Soluble mediators (e.g. complement)
Pattern recognition molecules
Components of adaptive immune system
Lymphocytes
Secreted Molecules
Antigen-recognition molecules (B and T cell receptors)
Adaptive immunity builds 2 responses
Humoral response that builds B-cells
Cell-mediates response that builds T-cells
What do helper T-cells do in adaptive immunity?
Activate and build antigenic class to release cytokines
What do killer T cells do In adaptive immunity ?
Build for killing of viruses
An antibody is composed of which 2 parts?
Constant region (effector function)
Variable region (antigen binding sites)
The antigen binding site on an antibody occurs on...
The light chain, it is where the "docking station" is
In an antibody, which chain contributes to antigen binding
Both chains contribute, the constant chain will not be recognized.
In adaptive immunity, Lymphocyte requires 2 signals
Signal that results from antigen binding to lymphocyte receptor
Signal delivered by an activating signal
- for T cells, this comes from antigen-presenting cells (dendritic cells and macrophages)
- for B cells, this comes from an activated t-cell
... Thus Adaptive immunity occurs on a cell that also presents an antigen.
Function of T lymphocytes
1. Cellular immunity: Helper T lymphocytes (macrophage activation, growth differentiation, stimulate B lymphocyte), cytotoxic T lymphocytes (lysis of infected cells, tumor and allografts)
2. Antigen recognition: antigen presentation by dendritic cells, macrophages and B lymphocytes, T-cell receptor
3. Cytokine Secretion
2 types of T-Lymphocytes
Cytotoxic T cells: kill infected cells
Helper T cells (2 types)
- TH1 release cytokines, chemokines that attract macrophages
- TH2 activation of B lymphocytes to aid in destroying extracellular pathogens
Function of Natural killer cells (NK)
- Innate cellular immunity
- Early component of host response
- Lysis of virus infected cells
- Posses receptors for self molecules that inhibit their activation against uninfected host cells
B Lymphocytes/plasma cells function
Humoral immunity
Antigen recognition
Antibody production
3 phases of adaptive immunity
Recognition of antigens
Activation of lymphocytes
Elimination of antigens
Which is the first Ig that can later build on any cell type
IgM, also IgD is important, from those 2 memory has to take place to give rise to IgG, IgA ad IgE
B cell receptors require how many diff binding receptors?
2, CD19 (killer cells) and CD21
Essentials of adaptive immunity
Clonal selection
Clonal Expansion
Clonal Deletion
Clone: is a group of cells activated to divide and generate function with identical progeny upon binding to the antigen
Are lymphocytes identical?
No 2 lymphocytes are identical
Small soluble proteins secreted by one cell that can alter behavior or properties of the cell itself or another cell
Cytokines
Chromatin clumping, Swollen organelles and Flocculent mitochondria
Necrosis
Leads to disintegration and inflammation
Mild convolution, chromatin compaction and segregation and condensation of cytoplasm
Apoptosis
Leads to phagocytosis
Immune cell recruitment to local site of infection/injury happens via activation/production of chemical signals by 2 methods...
via plasma derived factors (complement)
via cell-derived factors (constitutive & induced)
Complement cascade activation will do 3 things...
- Recognize/tag pathogens for improved destruction by immune cells by coating surface of pathogens (opsonization)
- Will recruit/activate immune cells via chemoattractant protein fragments to help clear dead cells
- Will poke holes (ionophore) in plasma membrane of an infected host or bacterial cell, causing cytolysis of infected cell & death of pathogen via "membrane attack complex" (c5b. c6, c7, c8, c9)
Present in high numbers in connective tissue, mature continuously. Long lived for days or weeks
Macrophages/Monocytes
First responding cell that is recruited , present in high numbers (50-60% of WBC). Not present in normal tissues, recruited in high numbers to site of infection/injury (diapedesis)
Can by oxygen depending or independent , and produce cytokines
Neutrophils (PMCs)
A type of macrophage with elongated cell processes, resident primarily in tissues exposed to external environment (skin, gingiva/langerhans. Long lived cells
Critical function as antigen-presenting cell
Dendritic cells
Respiratory mucosa (BALT and LALT
Gastrointestinal GALT
Skin SALT
The link between adaptive and innate immunity
Dendritic cells
The adhesion process is mediated by
cell-cell binding via receptor-counterReceptor interaction
Early inflammatory mediators like Histamine beings to vasodilate and start inducing expression of
P-selectin on endothelial surfaces
cytokines from injured cells express e-selectin
A primitive part of the immune system made of proteins expressed by cells of the innate immune system to identify 2 classes of molecules..
PRR (Pattern recognition receptors)
PAMPS (pathogen associated molecular patterns
DAMPS (damage associated molecular patterns
The humoral arm of the innate immune system
Complement system
Similarities in all complement systems
Reactions occur on cell surface
all generate homologous variants of c3-convertase
Which of the following statement(s) is/are correct?
a. Innate immunity includes natural mechanisms that exist before infection
b. Innate immunity is less evolved than the adaptive immunity
c. Adaptive immunity is specific but does not include memory
d. Mammals have both innate and acquired immunity capabilities
e. Rapid and early response to infectious agents can only be mounted through adaptive immunity
A, B and D
Natural Killer cells differentiate from myeloid lineage and are involved in acquired cellular immunity
False
Which of the following statement(s) is/are correct for lymphoid cells, tissues and organs?
a. Secondary lymphoid organs include tonsils and spleen
b. B lymphocytes mature at thymus in humans
c. Bone marrow is not a lymphoid organ
d. Each individual lymphocyte matures bearing a unique variant of an antigen receptor.
e. T cell selection takes place in bone marrow
A and D
According to Moutsopoulos and Konkel (2018) paper, which of the following statement(s) is/are correct?
a. Oral mucosal barriers are also main ecological habitats of the human body
b. Neutrophils are the dominating host cells in gingival crevice
c. Signals that regulate the gingival immunity are not unique compared to the other barrier sites elsewhere in human body
d. Host-microbe interactions and co-existence in the oral cavity represent commensalism
A, B and D
The Complement system consists of a plasma protein cascade that can be initiated by three pathways called the:
Classical, alternative and mannose-binding lectin pathways
According to Hajishengallis et al. (2019) paper, which of the following statement(s) is/are correct?
a. Complement system is important for homeostatic immunity; therefore, a dysregulated complement activation can lead to pathologies associated with inflammation.
b. Complement activation is independent of microbial dysbiosis
c. There is evidence that severe forms of aggressive periodontitis in humans present with defective complement activation.
A and C
According to the modified Koch’s postulates, what criteria are used in the determination of a periodontal pathogen?
D. a and c
16S rRNA is a good phylogenic molecule. What statement is true:
E. all of the above
According to the Krishnan et al. (2016) paper, which of the following statement(s) is/are correct?
a. While there is an abundance of data suggesting an association between oral infections and systemic diseases, it is yet to be established if there is a causal relationship between the oral microbiome and systemic pathologies.
b. Oral microbial taxa associated with health are the same microbial species associated with diseases.
c. Human Microbiome Project (HMP) provided a systematic approach to insights into what constitutes the normal microbiota of each organ or mucosa in the body, enabling a better understanding of how they impact human health.
d. Unlike many human diseases, oral bacterial diseases, such as caries and periodontitis, are not caused by a single oral species, but by a consortium of species that are likely living harmlessly in very low numbers (often below the limit of detection) in the oral cavity.
A, C and D
Among the following early theories on Caries Etiology, which one is the most relevant?
B. Chemo-parasitic theory---W.D. Miller (1890)
Of the following bacterial species, which TWO are considered “Principle caries-associated bacterial species”?
a. Fusobacterium nucleatum
b. Streptococcus mutans
c. Porphyromonas gingivalis
d. Lactobacillus fermentum
e. e coli
b and d
What are some of the characteristics of cariogenic bacterial pathogens?
a. Ability to produce acid (acidogenic)
b. Ability to more on the surface
c. Resistance to low pH (aciduric)
d. Ability to metabolize peptides
e. Ability to form biofilm
a, c and e
According to the Baker et al. (2019) paper, which of the following statement(s) is NOT correct for a precision therapeutic strategy in dentistry?
E. It is only limited to dental caries
The “Keystone Pathogen Hypothesis” states that
B. Low abundant periodontal pathogens change commensal c. bacterial flora to a dysbiotic, pathogenic one
What are key components of the ecological plaque hypothesis?
C. a, b, and c
According to Solbiati and Frias-Lopez paper (2018), which statement is false?
C. Microbial dysbiosis leads to fungal diseases
Which of the following statement(s) is/are false?
B. Periodontitis results from plaque accumulation, regards of the species present
Which of the following statement(s) is/are correct for lymphoid cells, tissues and organs?
a. Secondary lymphoid organs include tonsils and spleen
b. B lymphocytes mature at thymus in humans
b. Bone marrow is not a lymphoid organ
d. Each individual lymphocyte matures bearing a unique variant of an antigen receptor.
e. T cell selection takes place in bone marrow
A and D
Which of the following statement(s) is/are correct?
a. Innate immunity includes natural mechanisms that exist before infection
b. Innate immunity is less evolved than the adaptive immunity
c. Adaptive immunity is specific but does not include memory
d. Mammals have both innate and acquired immunity capabilities
e. Rapid and early response to infectious agents can only be mounted through adaptive immunity
A, B and D
Which of the following statement(s) is/are correct?
a. Innate immunity includes natural mechanisms that exist before infection
b. Innate immunity is less evolved than the adaptive immunity
c. Adaptive immunity is specific but does not include memory
d. Mammals have both innate and acquired immunity capabilities
e. Rapid and early response to infectious agents can only be mounted through adaptive immunity
A, B and D
Which of the following describes the balance between osmotic and hydrostatic pressures in the microvasculature?
C. Starling’s law
The initiation pathways of Complement generate C3-convertase. C3-converatse is important for proteolytic activation of C3 and subsequent initiation of the common pathway in the Complement system
Which statements are true/false
Both statements are true
Histatin 1 is primarily involved in mineral homeostasis within the oral cavity. Histatin 5& 3 are primarily involved in antifungal and antibacterial activity within the oral cavity.
Which statements are true/false
Both statements are true
Bacterial biofilms are generally comprised of the following
E. All of the above
The motor for bacterial flagella is driven by the following:
ATP
H+
NADH+
Sucrose
None of the above
H+
How many bacteria are present in the average human mouth?
700
50 billion
50 million
50 trillion
None of the above
50 billion
What is not true of the modified Koch’s Postulates?
E. Re-Isolate the causative microorganism in pure culture
In addition to mutans, which of the following bacterial can also be cariogenic:
a. e-coli
b. Pseudomonas aeruginosa
c. Actinomyces naeslundii
d. Scardovia wiggsiae
C and D
Which of the following are NEW techniques in studying oral microbiome
a. Spectrum imaging
b. 16s sequencing
c. Colony forming unit (CFU) testing
d. Meta-pangenome
A and D
What are the three MAIN factors of dental caries etiology:
Age
Gender
Diet
Bacteria
Tooth
Diet
Bacteria
Tooth
The following will affect periodontal disease pathogenesis
a. smoking
b. diabetes
c. LPS
d. a, b, and c
e. a and b
a. smoking
b. diabetes
c. LPS
Which statement is false?
B. Periodontitis results from plaque accumulation, regards of the species present
Which of the following is/are NOT true for the role of lipopolysaccharide (LPS) in inflammatory process?
C. LPS binds to CD14, which has a transmembrane domain so that CD14 can directly activate the intracellular signaling
Differences between the 3 complement pathways reaction
C3b is opsonization (
C3a and C5a have anaphylatoxin
C5b is a strong chemoattractant, increases phagocyte adherence to endothelial cells, initiates membrane attack complex
What are the three complement pathways
Classical pathway (need antigen antibody)
Lectin pathway (binding to pathogen surface protein/sugar)
Alternative pathway (pathogen surfaces)
** These are all ways to activate c3, through the enzyme convertase that cleaves c3 to get to c5, etc...
All of the complement pathways lead to these3 outcomes
1. recruitment of inflammatory cells (c5a)
2. Opsonization of pathogents to enhance phagocytosis (c3b)
3. Lysis of cells (c5b)
Decrease of vasodilation, vasopermeability, chemical mediators and leucocyte infiltration
Increase in regeneration of parenchymal cells
Resolution of inflammation
3 main types of changes in blood vessels with inflammation
vasodilation and hemostasis
vasopermeability
Activation of endothelial cells
Chemokine produced by Monocytes, macrophages, fibroblasts, keratinocytes and endothelial cells that mobilizes, activates, degranulates, neutrophils and creates angiogenesis.
IL-8
Functions of saliva
Pellicle formation
Mineral homeostasis
antimicrobial activity
Antimicrobial systems in saliva have as innate immunity
Lysozyme
Salivary Peroxidase
Lactoferrin
Mucins
Histatins
Bacteria in biofilm is ______ fold more resistant to antibiotics
1000 fold
The force of the flow of protons H+ across the bacterial cell membrane due to a concentration gradient set up by the cells metabolism
Proton Motive force
Factors that affect virulence
Surface appendages (pili, flagella)
Extracellular capsules, slime, antiphagocytic
Lipopolysaccharides
Exotoxins
Hydrolytic enzymes
Intracellular virulence factors factors
May serve as a reservoir in chronic diseases
Most accepted plaque hypothesis
Ecological plaque hypothesis
Ecological shift to gram negative causes more disease
Disease that results from the presence of one resident microbiota of certain body sites. Causes dysbiotic disease
Keystone pathogen hypothesis
Theory that says specific bacteria are not necessary, but not sufficient to cause disease
Socransky and Haffajee
Major outer membrane component of gram negative bacteria, considered an important factor in the progression of periodontal diseases
LPS Lipopolysaccharide
Characteristic of the surface antigen of monocytes and macrophages, principle binding element of LPS
CD14
Acute phase protein that has a normal serum concentration of 3-10ug/mL
LPS binding protein
Key cells in chronic inflammatory cells mediating the innate immune response to acquired immunity.