Mucosal Immunity - 2.4 PDF

**[Mucosal immunity - 2.4]** Mucosa associated lymphoid tissue (MALT) Functions Barrier to infection - **MALT in gastrointestinal tract** Specialised cells within the columnar, ciliated epithelial lining - - - - Peyers patches and MLNs - - - Lamina propria - - ![]...

**[Mucosal immunity - 2.4]** Mucosa associated lymphoid tissue (MALT) Functions Barrier to infection - **MALT in gastrointestinal tract** Specialised cells within the columnar, ciliated epithelial lining - - - - Peyers patches and MLNs - - - Lamina propria - -  **Oral cavity immune defenses** - **Soluble defences in saliva** **Antimicrobial properties of saliva** --------------------------------------------------- ------------------------------------------------------------------------------------------------------- **Antimicrobial agent** **Activity** α-Amylase Inhibits *P. gingivalis* Defensins (α&β) Cationic peptides with antibacterial, antiviral and immunomodulatory properties. Cystatins, secretory leukocyte protease inhibitor Inhibits microbial protease and thus its ability to metabolise proteins into amino acids. Histatins 1, 3 & 5 Inhibits *Candida albicans* Chitinase Antifungal with cell wall lysis properties. Statherin Inhibits anaerobic bacterial growth. Secretory IgA (also s-IgG, s-IGM) Inhibits adherence. Agglutinates bacteria. Virus neutralisation. IgA is the major antibody in saliva. Lactoferrin Fe^3+^ chelator that inhibits metabolic activity of microorganisms. Lysozyme Hydrolyzes glycosidic bond to damage bacterial cell wall - effective against *S. mutans*. Agglutinins Glycoproteins, mucins, fibronectin, 2-macroglobulin, proline rich proteins. Myeloperoxidase system Bactericidal in presence of thiocyanate/halide-H~2~O~2~. Salivary peroxidase system (enzyme thiocyanate/halide-H~2~O~2~) Complement (trace amounts) C3 -- probably largely derived from GCF Leukocytes \>98% are neutrophils, but up to 50% may not be capable of phagocytosis.  **Oral - pharyngeal cavity** - - - -  Oral langerhans cells - - - - - - **Gingivae**  **Gingival crevicular fluids** **T helper cells**  T cell homing to mucosal tissues 1. 2. 3. 4. - T helper 12 function Produce IL-17 - - -  T helper cells in oral pathologies **Oral mucosal immune pathologies** - - - - - - Oral lichen planus  Perio -  **Cancer** 48% of non-Hodgkin lymphomas are in extranodal regions eg salivary glands and oral cavity Most common extranodal lymphoma is MALT gastric lymphoma (secondary to Helicobacter pylori) Next most common is in salivary glands associated to Sjogrens syndrome (almost 50% of pt with salivary gland lymphomas have radiological evidence of Sjogrens syndrome)