Immunology Flashcards
What is the difference between microbiota and microbiome?
Microbiome = genetic material of microbes
Microbiota = Ecological community of commensal, symbiotic & pathogenic microorganisms.
What is the immune system?
Immune system – is a series of cells tissues, proteins and other that act together to counter act foreign bodies.
Why is it important for dental professionals to understand immunity?
- Due to advancements in medicine, people can now survive once fatal diseases
- Many oral diseases have an immune component (e.g. periodontal disease)
- Current and future therapeutics may have an impact on the function of immune system thus on oral health
- Systemic and Oral diseases are interrelated and are both dependent on appropriate function of the immune system
What is a pathogen?
Pathogens – are agents that cause or generate disease. Such as bacteria, viruses, fungi, dust mites, pollen.
What is an antigen?
Antigen – a substance that has the ability to provoke an immune response. Could be pathogenic/ not pathogenic.
What is the mode of action of an ACP?
- The antigen is detected y a special receptor on the ACP
- The antigen is engulfed through phagocytosis of the ACP
- It is processed and then displayed on the surface of the cell’s membrane of the ACP through a special antigen presenting proteins
- The presented antigen could bind with the receptor on T lymphocytes to activate them
What is an antibody?
Antibody – a glycorptoein that is produced and secreted by plasma cells and B lymphocytes (restricted thod). Also serve as receptors on B lymphocytes.
What are the classes of antibodies?
MADGE – IgM, IgA, IgD, IgG, IgE
What is a structure of the immunoglobulin?
Y shape, have variable and constant domains
What is the function of each immunoglobulin?
IgA – Found in mucous, saliva, tears and breast milk. Protect those sites against pathogens
IgD – Part of the B cell receptor. Responsible for basophils and mast cells activation.
IgE – Protects against parasitic worms. Responsible for allergic reactions
IgG – Secreted by plasma cells in the blood. Able to cross the placenta into the fetus.
IgM – May be attached to the surface of a B cell or secreted into the blood. Responsible for early stages of immunity.
What are the three functions of the antibodies?
- Neutralization
- Tag
- Activating antigen killing proteins
Why is immune system important for dental health professionals?
- Due to advancements in medicine, people can now survive once fatal diseases
- Many oral diseases have an immune component (e.g. periodontal disease)
- Current and future therapeutics may have an impact on the function of immune system thus on oral health
- Systemic and Oral diseases are interrelated and are both dependent on appropriate function of the immune system
What is a pathogen?
Pathogen is an agent that is able to cause or generate dieseas?
What is an antigen?
An antigen is a substance that has the ability to provoke an immune response. This could be pathogenic/not pathogenic
What is an immunoglobulin?
An immunoglobulin is also know is an antibody. It is a glycoprotein that produced by pklasma cells and somewhat by B lymphocytes.
Antibodies also act as receptors on B lymphocytes.
What are the three functions of the antibody?
- Neutralisation - physical blockage of the antigen
- Tag - antibodies act as “tags”, that are able to signal phagocytic bacteria to perform phagocytosis of the molecule antibodies attach to.
- Activating antigen killing proeins - self-explanatory
What is an ACP?
ACP is an antigen presenting cell.
It is a cell that is able to process the antgien and present it to other cells.
It could also trigerr further immune reponse by releasing cytokines.
What are some of the common antigen presenting cells?
- Dendritic cells
- Macrophages
- Langerhans cells
- B lymphocytes
What is the mode of action of an ACP?
- Antigen is detected by a special receptor on the ACP
- The antigen engulfed through phagocytosis of the ACP
- It is processed and then displayed on the surface of the ACP cell membrane through special antigen presenting protein
- The presented antigen could bind with the receptor on T lymphocyts to activate them
What are cytokines?
Cytokines are the chemicals of immunity. They are rpoduced by activated cells and are able to change the behaviour of other cells.
What is a strucutre of immunoglobulins?
Y shape, have variable and constant domains
WHat is the function of IgA?
It is found in mucous, saliva and tear. Protect those sites from pathogens
What is the function of IgD?
It acts as a B cell receptor. Responsible for basophil and mast cells activation
What is the function of IgE?
Protection against paracitic worms. Important in allergic reactions.
What is the function of IgG?
Secreted by plasma cells in the blood. Able to cross the placenta into the fetus.
What is the function of IgM?
Responsible for early stages of immunity.
What are the two types of lymphatic organs?
- Primary - generator organs - red bone marrow and thymus
- Secondary - immune and other functions - lymphoid vessels, lymph nodes, spleen and follicles.
What are the lymphatic vessels?
They are thin walled ubes lined with endothelium and surorunded by thin layer of smooth muscles. Carry lymph. Terminate near the subclavian artery.
What is the spleen?
Spleen is the organ of the secondary lymphati system. it has 2 functions filtering blood form the ntigen and removal of old red blood cells
What is the thymus?
It is an organ of the primary lymphatic system that is used for development/maturation of T lymphocytes. It has a plae center with activated T lymphocytes.
What are lymph nodes?
They are organs of the secondary lymphatic system that are used for antigen presentation.
What are lymphoid follicles?
They are organs of the secondary lymphatic system that are situated under the epithelium for protection from ferieng invaders
What is the waldeyer’s tonsilar ring?
It is a series of tonsillar tissue that forms a ring around the oral cavity in addition to the lymphatic between each of the 3 major tonsils. Main function - to provide protection aginst harmuf substances and pathogens that may enter the body through the nose and mouth.
What are MALT?
MALT - mucosa associated lymphoid tissue.
WHat are the two major areas of immunity?
Innate - non-specific immunity
Acquired - specific immunity
What are the main defence mechanisms of the innate immune system?
- Physical barriers (epithelium and saliva for example)
- Chemical barrier (proteins in saliva)
- Cellular components (neutrophils, mast cells, macrophages etc.)
What are the main defensive mechanisms of the adaptive immune system?
- Humoral (memory B lymphocytes and plasma cells)
- Cellular (T lymphocytes, NK cells and NK T cells)
What are the main differences between the innate and adaptive defense systesms?
Innate system is considerably faster, less specific and unable to amplify it’s efficiency upon repeated antigen presentation.
Addaptive system is slower, more specific and able to amplify it’s efficiency upom repeated antigen presentation.
What is oponization?
It is a process of marking an antigen for phagocytosis
What are PRR?
PRR are the pattern recognition receptors, they are receptors that identify potential pathogens.
What do you know about neutrophils?
They are a cell with a many shaped nuclei - respond by chemotaxis from chemokine release and use diapedesis to get to the site of tissue injury - release granules - have an antimicrobial effect.
What do you know about macrophages?
Macrophages are a form of a monocyte - used for phagocytosis and antigen presentsation - Use PRR receptors
What do you know about eosinophils?
They are a type of granulocyte - kill large parasites - contain large number of enzymes
What are mast cells?
They are cells that contain potent substances - cells that induce chemotaxis - one of the most important signaling cells in inflamation
What are dendritic cells?
They are cells that have similar function to macrophages and actually have similar origin - act as messengers and antigen presenters
What are natural killer cells?
They are a non-T and a non-B lymphocyte - they recognise infected or transformed cells through the MCT II recpetor - f a cell does not have an MHC receptor it must be killed
What are the 7 steps of phagocytosis?
- Chemotaxis and adherence of microbe to phagocyte
- Ingestion of microbe via phagocytosis
- Formation of a phagosome
- Fusiion of phagosome with lysosome to form a phagolysosome
- Digestion of the ingested microbe by enzymes
- Formation of residual body containing indigestible material
- Discharge of waste materials
What are the 4 important aspects of phagocytosis?
- MHC receptors used for recognition
- Receptor - ligand engagement that induces cytoskeletal and membrane remodeling
- Perticle engulfment
- Destruction
What is inflamation?
Iflamation is an innate immune response that is protective, non-specific and results in a series of interrelated events.
What are the three goals of inflamation?
- Isolate, detsroy or inactivate
- Remove debris
- Prepare for healing
What are the 4 cardinal signs of inflamation?
Redness, Swelling, Heat, Pain
What causes the redness in inflamation?
It is caused by increased blood flow tp the area
What causes swelling in inflamation?
It is caused by increased leakage of protein rich fluid om the tissue are due to increased capillary permeability as a result of vasodialation.
What causes heat in inflamation?
Heat is caused by increased blood flow to the area - this increase in heat increases the metabolic rate of cells
What causes pain and loss of function in inflamation?
The pain is caused by increased leakage of protein rich fluid into the tissue that aggrevates the nerve endings.
What is the sequence of event during inflamation?
- Brief vasocontriction
- Vasodialation - mediated by mast cells
- Increased vasuclar permeability - to small proteins not cells (cause of edema is due to release of water due to colloid osmotic prssure)
- Transmigration - chemotaxis and increased cell wall permeability allw=ows for extravasion and leukocyte migration
- Phagocytosis
- Healing
What are the two components of aquired immunity?
- Cellular - production of Suppressor, Cytotoxic and Helper T cells. This is targeted for desctructionn of already infected body cells
- Humoral - B cells differentiate into plasma cells and B memory cells
How can the aquired immune system eliminate the pathogen?
- Antibodies - derived from plasma cells
- Cytotoxic cells - attack directly or discharge granules
What happens during the lymphocyte activation?
- Antigen are processed by the phagocytes
- They are presented on modified MHC II and I receptors
- MHC II receptor is able to bind with CD4+ T lymphocyte and creat a Helper T cell which than continue the cascade to activate B cells
- MHC I receptor is able to bind with CD8+ T lymphocyet and creat Supressor and Cytotoxic T lymphocytes
What are the steps of CD4+ cell activation process?
- Foreign antigen phagocytes, killed & processed by the APC
- ACP presents processed fragment
- This is done via MHC II molecule (epitode) on the membrane surface of the APC
- Epitode binds with TCR on naive CD4+ T lymphocyte
- This causes activation of the naive CD4+ T lymphocyte and creates a T helper cell
- T helper is able to bind with a B lymphocyte and cause it to transform into either B memory cell or plasma cell
How do vaccines work?
Vaccines are able to present the antigens in weakened form in order go through the acquired immunity response to create sophisticated Plasma Cells that can produce specifc antibodies for the antigen, in order to eliminate the antigen faster when it is presented in the system next time.
What is herd immunity?
It is a refrence to the population where 70-80% of people are vaccinated. This reduces person-to-person transmission, thus this protects the unvaccinated individuals.
What is an autoimmune diseases?
It is a condition where bodies own antibodies develop specificity towards the bodies own tissue. This is due to defects in the aquired immune system.
What are the four allergy specification?
Type I - immediate response (anaphylaxis)
Type II - Transfusion (hours)
Type III - Immune complexes (days)
Type IV - Delayed (weeks)
What is Type I hypersensitivity?
It is an excessive immune response to harmless antigen. Involved are mast cells (degranulation processes caused by binding with IgE), B cells and T helper cells.
What are the steps of Type I hypersentivity?
- Antigen is processed as usual and Plasma cells are created with a speicifc IgE antibody
- IgE antibody binds with a mast cells and act as a receptor
- If the antigen apprearce again and binds with IgE receptor on the mast cell it will cause degranulation
What is the resident flora?
Resident floral conssts of relativley fixed type of microorganisms regularly found in the oral cavity at a given age. It reastablishes quickly.
What is transient flora?
It is a group of bacteria that consists of non-pathogenic or potentially pathogenic microorganisms that inhabit the oral cavity for hours/day. They do not establish themselves permenantly.
So how does transient flora replace resident flora?
The resident flora can be disturbed or the host resistance can change. This will cause the transient microorganisms to colonize the freed niches, proliferate and produce disease.
Why do bacteria colonise teeth?
Because teeth are solid and non-shedding surfaces and that is why bacteria prefer to colonize them.
What are the 6 major niches for bacteria in the oral cavity?
- Tongue
- Tonsils
- Hard, non-shedding surfaces
- Gingival Sulcus
- Mucosa
- Saliva
What is the gram system and how does it separate bacteria?
Gram system separates the microorganisms in 2 distinct groups
- Gram positive - blue in clour - min bacteria in periodontal bacteria
- Gram negative - pink in colour - contain LPS - major driver of inflamatory reaction
What are the stpes of sulcus colonization?
- Early colonization from gram positive cocci microorganism
- Secondary colonization by gram positive and negative rods
- Late colonization by gram negative rod and motile bacteria
- Microbial succession – dominance of microorganisms
What happens to the aerobic/anerobic transition during the colonization of the sulcus?
The bacteria transition from mostly aerobic at the early colonization to mostly anaerobic. This happens due to the fact that as bacteria grow – the biofilm also grows, meaning that the aerobic bacteria that get covered by the biofilm transition to an anaerobic state due to lack in oxygen.
What are the physical barrier system in the sulcus?
- Epithelial desquamation – constant shedding of the epithelial cells does not allow the bacteria to attach to those surfaces
- Saliva flow – pick up and moves the bacteria
- Soft tissue movement – moves the biofilm
- Mastication – moves the biofilm
What are the chemical barriers in the sulcus?
- Saliva – has antibacterial action – Immunoglobulin A, lysozymes, lactoperoxidase
- Antimicrobial Peptides – peptides stored in saliva, used for destruction of bacteria and more
What is GCF?
GCF is gingival crevicular Fluid. It is the transudate or exudate of the periodontal tissues collecting sulcus. It has 4 functions: 1. Cleansing the sulcus 2. Antimicrobial function 3. Antibody activity 4. Cell adhesion.
What are the two theories of GCF source?
Theory 1: Increased permeability due to inflammation in the capillaries near the sulcus.
Theory 2: Fluid is in a form of transudate due to osmotic gradient. And upon inflammation becomes an exudate.
What is the function of Junction Epithelium in the periodontal defense system?
The junction epithelium has a very fast turn over rate, meaning it is constantly shedding. This results in inability for the bacteria to attach to junction epithelium. Also the shedding of cells outside the sulcus, physically pushes bacteria that are floating around the sulcus (this occurs with help of Gingival Crevicular Fluid).
What are PMNs?
Polymorph nuclear Neutrophils (neutrophils)
How are neutrophils move into the oral cavity?
Through junction epithelium. They have three modes of action: 1. Phagocytosis 2. Granulation 3. NETosis (neutrophils extracellular traps – extinction of chromatin in the extracellular space that kills bacteria)
What is the definition of periodontal health?
Periodontal health should be defined as a state free from inflammatory periodontal disease that allows an individual to function normally and not suffer any consequences as a result of past disease.
What is pristine periodontal health?
It is defined as total absence of clinical inflammation and physiological immune surveillance on a periodontium with normal supports
What is clinical periodontal health?
It is defined as absence or minimal levels of physiological immune surveillance or clinical inflammation in periodontium with normal support
