IM2: Oral Immunity Flashcards
1. Importance of the oral cavity in health and disease 2. Describe physical, chemical and biological effects of salivary and crevicular fluids 3. Recognise non-specific and specific defence mechanisms in the oral cavity 4. Appreciate the role of immune responses in oral defence mechanism
Describe the physical and chemical barriers in oral immunity
- Mucus coating layer = viscous fluid with high mucin content to trap pathogens - produced by salivary glands
- Epithelial physical barrier = also produces antibacterial and pro-inflammatory molecules e.g. TLR, PRRs, calprotectin, B-defensins, IL-18
- Saliva: slgA, IgM, lysozyme, peroxidase, lactoferrin, agglutinins, cystitis, histatins
- Gingival crevicular fluid = inflammatory exudate derived from periodontal tissue (serum antibodies, complement, cytokines, lysozyme, peroxidase, neutrophils and lysosomal components)
Role of lysozymes in saliva
Break down carbohydrates in bacterial cell walls at high pH
Role of lactoferrin in saliva
Hydrolyses RNA, anti-viral, bacterial and parasitic functions due to iron deprivation
Role of lactoperoxidase in saliva
Pro-inflammatory
Role of immunoglobulins in saliva
Peroxidation of organic compounds - this damages cell membrane of microorganisms
Role of chromogranin A in saliva
Contributes to formation of secretory granules
Role of GCF
Maintains the structure of junctional epithelium and the antimicrobial defence of the periodontium
Which immunological cells are always present in the mouth
Neutrophils continuously transmigrate through the junctional epithelium to patrol and inspect microorganisms in the biofilm
T/B lymphocytes, innate lymphoid cells and phagocytes are also present
How are secondary lymph organs and oral-associated lymphatic networks associated with oral immunity
This is where B cell proliferation and expansion occurs following antigen presentation (in the B cell follicle) and T cell area - dendritic cells are also present here
Role of histatinins in saliva
Neutralise toxins, chelation, protease and cytokine inhibition
Role of cystitis in saliva
Inhibit cytosine proteases, regulates host cell proteolytic activity
Role of peroxidase in saliva
Diffuse into bacteria and interfere with metabolic pathways
Role of mucins in saliva
Selectively permeable thick and slippery so prevent bacterial adhesion
Physical barriers in oral immunity
- adherent mucin layer
- desquamation (limits bacterial colonisation)
- epithelial Ab receptors
- acquired enamel pellicle
