Understanding the cellular components of the immune system.pptx

role of mast cells in immunity

1. Mast cells – a role in periodontal diseases Steinsvoll S, Helgeland K, Schenck K. J Clin Periodontol 2004. Dr. Ruchika Guleria MDS 1 st Year

2. The immune system is a complex network of cells and proteins that defends the body against pathogens . Understanding its cellular components is essential for comprehending how we fight infections and maintain health . I N T R O D U C T I O N T O I MM U N O L O G Y

3. The immune system consists of two main b r a n c h e s: i nn a t e a n d a d a p ti v e i m m u nity . The innate response is immediate and non- specific, while the adaptive response is slower but highly specific. Both systems work t o g e th e r t o p r o t e c t the b od y f r om d is e a se . O V ER V I E W O F I MM U N E S Y S T E M

4. White blood cells, or leukocytes , are crucial to the immune response. W H I T E B L OO D C E LL S They are divided as Each type plays a unique role in identifying and eliminating pathogens .

5. Granulocytes, including NEUTROPHILS , EOSINOPHILS , and BASOPHILS , are essential for the innate immune response . They respond quickly to infections and are involved in inflammation and allergic reactions, providing immediate defense. G R A N U L O C Y T E S

6. L y m p h o c y t e s a r e a k e y c o m p o n e n t o f t h e a d a p ti v e i m m u n e s y s t em . Th e y in c l u de B c e lls , w h ich p r o du c e a n ti b o di e s , a nd T c e lls , w h ich k ill i n f e c t e d c e lls. U nd ersta nd ing th e ir fun c ti o n s is vit a l f or d e v e l o p ing v a c cine s a n d therapies. L Y M P H O C Y T E S O V ER V I E W

7. T c e lls p l a y di v erse r o l e s in the i m m une response. Helper T cells assist other immune cells, while cytotoxic T cells directly kill i n f e c t e d c e ll s . T h e i r a cti v a ti o n a n d proliferation are essential for a robust immune response . T C E LL S F U N C T I O N S

8. B c e lls a r e r e s p o nsi b le f o r p r o d uci n g antibodies , which bind to specific antigens on pathogens. This binding neutralizes the threat a n d m a r k s it f or d e s tructi o n. T he a bility t o remember past infections is crucial for immunity . B C E LL S A N D A N T I B O D I E S

9. M o n oc y t e s a r e l a r g e w hi t e blo o d c e lls t h a t differentiate into macrophages when they migrate into tissues. Macrophages are vital for phagocytosis , engulfing and digesting p a tho g e n s , a nd p r e s e n ti n g a n t i g e n s t o T c e lls. M O N O C Y T E S A N D M A C R O P H A G E S

10. Dendritic cells are antigen-presenting cells that bridge the innate and adaptive immune systems. Th e y ca p t u r e a nd p r o c e ss a n tige ns, a cti v a ting T cells and initiating the adaptive immune response. Their role is critical for effective immunity . D E N D R I T I C C E LL S

11. C y t o k in e s a r e s m a ll p r o t e ins t h a t f a cilit a t e c o mm uni ca ti o n b e t w een i m m u n e c e lls. Th e y regulate immune responses, inflammation, and hematopoiesis. Understanding cytokine signaling is crucial for developing treatments f o r a u t oi m m u ne d ise a s e s a n d i n f e c ti o ns . C Y T O K I N E S A N D S I G N A L I N G

12. Disorders of the immune system can lead to autoimmune diseases , allergies, and immunodeficiencies. Understanding the cellular components helps identify potential targets for therapies and improve patient outcomes in these conditions. I MM U N E S Y S T E M D I S O R D E R S

13. MAST CELLS Aka mastocyte / labrocyte

14. F irst reported by Friedrich von Recklinghausen in 1863 : described the presence of granulated cells in unstained connective tissues. Later described by Paul Ehrlich in 1876 ( Mastzellen , meaning well-fed cells) MCs are derived from multipotential stem cells in the bone marrow MCs have been implicated in multiple diseases, such as mastocytosis , mast cell activation syndrome (MCAS), osteoporosis, autoantibody-mediated arthritis, multiple sclerosis, allergic reactions, and numerous lung pathophysiologies . One hallmark in mast cell development is that c-kit (CD117 )

15. ORIGIN

16. DIFFERENCE BETWEEN MAST CELLS AND BASOPHILLS

17. MAST CELL HETEROGENITY C ontains both tryptase and chymase (MC TC ) Contains tryptase (MC T ).

18. Mast cells play important roles in mucosal inflammation, host defense and tissue repair. When triggered by locally produced cytokines or bacterial products (e.g. lipopolysaccharides), the cells can release large quantities of pre-stored mediators such as histamine, leukotrienes, platelet-activating factor (PAF), proteases and tumor necrosis factor-a (TNF- α ). Mast cells are seen scattered throughout gingival CT, often in close association with endothelial cells, but are also found sub- and intra- epithelially . MUCOSAL MAST CELL

19. MAST CELL STAINING Mast cells are not readily identified in heamatoxylin and eosin stained sections. Metachromatic dye technique are used for staining such as Toluidine Blue and Azure A.

20. Pararosaniline is preferred as it forms an insoluble red/pink reaction product.

21. MAST CELL MEDIATORS

22. PERFORMED MEDIATOR Histamine S ynthesized in the Golgi apparatus by decarboxylation of histidine and stored in granules at 100 mM concentration. Once released, methylation and oxidation rapidly catabolize histamine.

23. 2) Heparin 3) Tryptase 4)Chemotactic Factors 5) Chymase

24. NEWLY FORMED MAST CELL MEDIATORS (DE NOVO) PGD2 2) PAF

25. In humans a broad spectrum of cytokine protein and/or mRNA has been identified in mast cell lines or in vivo-derived mast cells . including SCF, TGF-b1, TNF- α , bFGF , IL-1 β , IL-3, IL-4, IL-5, IL-6, IL-8, IL-13, MIP-1 α , MIP-1 β , RANTES, I-309 and MCP-1 (Lin & Befus 1999). MAST CELL CYTOKINES

26. MAST CELL RECEPTOR

27. MAST CELLS IN WOUND HEALING Mast cells are known to participate in three phases of wound healing 1) The inflammatory reaction 2) Angiogenesis 3) Extracellular- matrix reabsorption

28. MAST CELL MMPS IN PERIODONTAL DISEASES C ell migration Wound healing Tissue remodeling Pathogenic role in Periodontitis and Arthritis Mast cell strongly express MMP-1, MMP-8, MMP-2 and TIMP-2. In a recent study , Næsse et al. (2003) found that gingival mast cells were the foremost producers of MMP-1.

29. MAST CELL DISEASES MASTOCYTOSIS Is a heterogenous group of disorders characterized by abnormal growth and accumulation of mast cells in skin and sometimes other organs such as bones, liver, GIT and spleen. BIOMARKERS OF MASTOCYTOSIS Increased plasma and urinary levels of histamine and its metabolite methyl imidazole acid. Increased PGD2. Increased plasma tryptase level.

30. Mast cell leukaemia Mast cell leukemia (MCL) is a very rare form of aggressive systemic mastocytosis accounting for < 1% of all mastocytosis . It may appear de novo or secondary to previous mastocytosis and shares more clinicopathologic aspects with systemic mastocytosis than with acute myeloid leukemia. Symptoms of mast cell activation—involvement of the liver, spleen, peritoneum, bones, and marrow—are frequent.

31. DISCUSSION Realtionship between mast cell counts and different types of periodontitis was studied by S. Varabhi et al. in 1983 .

32. Gingival specimens were taken from 20 moderate-to-advanced chronic and 19 moderate-to advanced aggressive periodontal sites as case groups and 18 healthy/gingivitis sites as control group in routine periodontal flap and crown lengthening procedures. Mast cell counts were higher in chronic versus aggressive periodontitis and healthy/gingivitis cases (P = 0.000). The aggressive periodontitis cases did not demonstrate higher counts of mast cells as compared to healthy/gingivitis cases (P >0.05). There was no relationship between mast cell counts and degree of inflammation in the three groups.

33. In conclusion, the cellular components of the immune system play vital roles in defending against pathogens. A thorough understanding of these components enhances our ability to develop effective therapeutics and vaccines , ultimately improving health outcomes. C ONCLUSION

34. T hank you !