CELLS OF IMMUNE SYSTEM-1.pptx

PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY,SRI PARAMAKALYANI COLLEGE, ALWARKURICHI.

1. SRI PARAMAKALYANI COLLEGE ( Reaccredited with B Grade with a CGPA of 2.71 in the II Cycle by NAAC Affiliated to Manonmaniam Sundaranar University, Tirunelveli) ALWARKURICHI 627 412 TAMIL NADU, INDIA POST GRADUATE & RESEARCH CENTRE - DEPARTMENT OF MICROBIOLOGY (Government Aided) I I SEM - CORE – IMMUNOLOGY UNIT – 1 CELLS OF THE IMMUNE SYSTEM M.MOHAMED FAISAL REG NO: 20211232516114 I M.SC.MICROBIOLOGY ASSIGNED ON: TAKE ON : Submitted to , GUIDE: Dr.S.VISWANATHAN, Ph.D , ASSISTANT PROFESSOR & HEAD OF THE DEPARTMENT , SRI PARAMAKALYANI COLLEGE, ALWARKURICHI .

2.   OUTLINE I ntro d uct i on   Format i on of b l ood cel l s T ypes of l eucocytes Cells of the i nnate i mmune system Phagocytos i s and int r a cellular killing Cells of the a da p t i ve i mmune system Cell-Me d i ated Cytotoxicity lmmunopathology Conclusion References    

3. Introduction White blood cells or leucocytes serve as defenders against infection. They move arou n d the body via the lymph a tic and b l ood circulatory systems. Leucocytes are classified by morphology- number of nuclei lobes and presence or absence of cytoplasmic granules. Leukocytes may be found as i n divi d ual cel l s throughout the b od y , as accumul a tions w i thin l ymphoid organs (e . g . , splee n , lym p h no d es) a nd a t sites of infection or infl a mm a tion.

4. Formation of blood cells All blood borne cells origin ate in the bone marrow. Pluripotent hematopo i et i c stem cell in the bone marrow give r i se to two major line a ges; a myelo i d l ineage and a lym p hoid l ineage.   Cells of the myel oid li neage differentiate further i nto p l atelet s , erythrocytes , eosinophils , basophils (and mast ce l ls ) , neutrophils , monocyte s / macroph a ge s , and some dendritic cell s .

5.   TYPES OF LEUKOCYTES White blood cells th a t have mu l tilobed nuclei and contain conspicuous cytoplasmic granules are known as granulocytes .   O thers with a sing l e, unlobed nuc l eus a nd cytop l a sm th a t cont a ins few or no gr a nu l es are known as agranular leukocyte s .

6. Ce l l s of t h e i n nate i m m u n e system   • Myeloid Cells: F i rst li ne of de f ense a gainst i nv a ding organisms in non-specif i c inn a te i mmun i t y . • Ne u trophi l s • Eosinophils • B a sophils/Mast cells • Monocytes/M a cro p hages/Den d rit i c Cells

7. EOSINOPHIL Eosinophil has bilobed nuclei and cytoplasmic granules that stain with the acid dye eosin It constitutes 1% to 3% of circulating leucocytes It involves in asthma

8. BASOPHILS Basophils have bilobed nuclei and cytoplasmic granules that stain with the basic dye methylene blue. Found in low numbers in the blood (< 1°/o). Act like mast cells. They are nonphagocytic . Involved in allergic reactions (Type I hypersensitivity responses). Have high affinity Fe receptors for lgE on their surface. When an individual is exposed to an allergen, specific lgE is produced. This lgE binds to the surface of basophils.

9. NATURAL KILLER CELLS Also known as l arge granular lymphocytes (LGLs )   Functionally cytotoxic representing an innate Population that kill v i rally infected or tumor target cells .   Killing is nonspecific - they do not need to recognize for e i gn an t i gens presented on the target cell. NK cells do not have a specific cell receptor.Target recognitio n occurs b y a Killer Inhibitory Receptor, KIR, which assess MHC 1 molecules on the target cell surface MHC 1 molecule is lacking on infected and tumor targets.  

10. PHAGOCYTOSIS AND INTRACELLULAR KILLING Phagocytosis is the engulfment and degradation of microbes and other particulate matter by cells such as macrophages/ monocytes , dendric cells, and neutrophils .  Steps in phagocytosis- 1.Detection of the foreign particle and movement of the phagocyte to the area by chemotaxis . 2.Attachment of the foreign particle to the phagocyte. 3.Engulfment or ingestion of the foreign particle into a vesicle called a phagosome. 4.Fusion with lysosome and formation of the phagolysosome . 5.Intracellular killing and digestion. .  

11. C onclu s i on The immune system has evolved to protect us from p a t h ogens. Phagocytes and lymphocytes are key mediators of immunit y . Phagocytes i nternalize p a thogens and d egr a de them. L ymphocytes (B and T cells) have rece p tors that recognize specific molecular components of pathogens and have specia l ized functions. B cells make antibodies (ef f e ctive against extr a cel l ular p a thogens) , cytotoxic T lymphocytes (CTLs) kill virally i nfected c e ll s , a nd helper T cells coordinate the immune response by direct cell-cell interactions and the release of cytokines.

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