TheThe ImmuneImmune SystemSystem Xue Hui DepartmentDepartment ofof HistologyHistology && EmbryologyEmbryology IntroductionIntroduction ComponentsComponents FunctionFunction Macrophage MechanismsMechanisms ofof ImmunityImmunity StructuralStructural componentscomponents ofof thethe immuneimmune systemsystem Immune cell Lymphocyte Antigen presenting cell Plasma cell Granulocyte Immune tissue ( Lymphatic tissue ) Diffuse lymphoid tissue Lymphoid nodule Immune organ ( Lymphatic organ ) Central lymphoid organ Peripheral lymphoid organ LymphocyteLymphocyte SmallSmall lymphocytelymphocyte Diameter:Diameter: 66 ~~ 88μμmm MediumMedium -- sizedsized lymphocytelymphocyte Diameter:Diameter: 99 ~~ 1212μμmm LargeLarge lymphlymphocyteocyte Diameter:Diameter: 1313 ~~ 2020μμmm LymphocyteLymphocyte Medium - sized lymphocyte (Left) & Small lymphocyte (Right) LymphocyteLymphocyte LymphocyteLymphocyte ThymusThymus dependentdependent lymphocytelymphocyte (T(T cell)cell) HelperHelper cellcell (Th(Th cell)cell) CytotoxicCytotoxic cellcell (Tc(Tc cell)cell) MemoryMemory cellcell BoneBone marrowmarrow dependentdependent lymphocytelymphocyte (B(B cell)cell) NaturalNatural killerkiller cellcell (NK(NK cell)cell) LymphocyteLymphocyte T Cell NK Cell B Cell StructuralStructural ComponentsComponents ofof thethe immuneimmune systemsystem Immune cell Lymphocyte Antigen presenting cell (APC) Plasma cell Granulocyte Immune tissue ( Lymphatic tissue ) Diffuse lymphoid tissue Lymphoid nodule Immune organ ( Lymphatic organ ) Central lymphoid organ Peripheral lymphoid organ LymphaticLymphatic tissuetissue DiffuseDiffuse lymphaticlymphatic tissuetissue Postcapillary venule LymphaticLymphatic nodulenodule PrimaryPrimary lymphoidlymphoid nodulenodule SecondarySecondary lymphoidlymphoid nodulenodule GerminalGerminal centercenter DiffuseDiffuse lymphoidlymphoid tissuetissue && LymphoidLymphoid nodulenodule Postcapillary venule LymphoidLymphoid nodulenodule ↓: Afferent lymphatic vessels ※ : Subcapsular sinus D : Dark zone L : Light zone C : Cap LymphaticLymphatic organorgan CentralCentral lymphaticlymphatic organorgan ThymusThymus BoneBone marrowmarrow PeripheralPeripheral lymphaticlymphatic organorgan LymphLymph nodenode SpleenSpleen TonsilTonsil ThymusThymus StructureStructure ofof thethe thymusthymus CapsuleCapsule InterlobularInterlobular septumseptum ParenchymaParenchyma ThymicThymic lobulelobule CortexCortex -------- DarkDark stainingstaining MedullaMedulla -------- LightLight stainingstaining ThymusThymus ★★ △△ Capsule △Cortex ★Medulla ThymusThymus StructureStructure ofof thethe thymusthymus ReticularReticular connectiveconnective tissuetissue EpithelialEpithelial reticularreticular cellcell ThymusThymus cortexcortex ThymusThymus epithelialepithelial cellcell (epithelial(epithelial reticularreticular cell)cell) SubcapsularSubcapsular epithelialepithelial cellcell NurseNurse cellcell InterdigitatingInterdigitating dendriticdendritic cellcell ThymocyteThymocyte ThymusThymus matrixmatrix cellcell ThymusThymus Subcapsular epithelial cell Interlobular septum Nurse cell Thymocyte Cortex Interdigitating dendritic cell Macrophage Interdigitating dendritic cell Medulla Medullary epithelial cell Thymic corpuscle epithelial cell Thymus E: Epithelial reticular cell T: Thymocyte ThymusThymus medullamedulla ThymusThymus epithelialepithelial cellcell MedullaryMedullary epithelialepithelial cellcell ThymicThymic corpusclecorpuscle epithelialepithelial cellcell ThymicThymic corpusclecorpuscle (( oror HassallHassall’’ss corpusclecorpuscle )) MatureMature thymocytethymocyte MacrophageMacrophage ThymusThymus Subcapsular epithelial cell Interlobular septum Nurse cell Thymocyte Cortex Interdigitating dendritic cell Macrophage Interdigitating dendritic cell Medulla Medullary epithelial cell Thymic corpuscle epithelial cell Thymus medulla Thymic corpuscle H: Thymic corpuscle or Hassall corpuscle BloodBlood –– thymusthymus barrierbarrier EndotheliumEndothelium ofof continuouscontinuous capillarycapillary BasementBasement membranemembrane aroundaround endotheliumendothelium PeriPeri--vesselvessel spacespace aroundaround capillarycapillary ,, whichwhich containscontains macrophagesmacrophages BasementBasement membranemembrane ofof epithelialepithelial reticularreticular cellscells ProcessesProcesses ofof epithelialepithelial reticularreticular cellscells BloodBlood –– thymusthymus barrierbarrier Processes of epithelial reticular cells Cell junction Basement membrane of epithelial reticular cells Endothelium of continuous capillary Basement membrane around endothelium Peri-vessel space Macrophage Lymphocyte BloodBlood –– thymusthymus barrierbarrier FunctionFunction ofof thethe thymusthymus TheThe thymusthymus isis thethe sitesite ofof thethe terminalterminal differentiationdifferentiation andand selectionselection ofof TT lymphocytes.lymphocytes. TheThe thymusthymus produceproduce severalseveral proteinsproteins thatthat actact asas growthgrowth factorsfactors toto stimulatestimulate proliferationproliferation andand differentiationdifferentiation ofof TT lymphocytes.lymphocytes. LymphoidLymphoid organorgan CentralCentral lymphoidlymphoid organorgan ThymusThymus BoneBone marrowmarrow PeripheralPeripheral lymphoidlymphoid organorgan LymphLymph nodenode SpleenSpleen TonsilTonsil Lymph node Lymph node ParenchymaParenchyma ofof thethe lymphlymph nodenode CortexCortex SuperfacialSuperfacial cortexcortex LymphoidLymphoid nodulenodule DiffuseDiffuse lymphoidlymphoid tissuetissue ParacortexParacortex zonezone (Deep(Deep cortexcortex unit)unit) Postcapillary venule CorticalCortical sinussinus SubcapsularSubcapsular sinussinus PeritrabecularPeritrabecular sinussinus MedullaMedulla MedullaryMedullary cordcord MedullaryMedullary sinussinus SuperfacialSuperfacial cortexcortex andand deepdeep cortexcortex unitunit ofof lymphlymph nodenode Afferent lymphatic vessel Lymphoid nodule Deep cortex unit (Central zone) Deep cortex unit (Peripheral zone) Medulla Lymph node SuperfacialSuperfacial cortexcortex ofof thethe lymphoidlymphoid nodulenodule ↓: Afferent lymphatic vessels ※ : Subcapsular sinus D : Dark zone L : Light zone C : Cap Cortex of the lymph node Paracortex zone of the lymph node Postcapillary venule Postcapillary venule in the lymph node Reticular cell High endothelial cell Lymphocyte Lymphocyte Lymphocyte Nuclear of endothelial cell Lymphocyte Postcapillary venule in the lymph node Postcapillary venule lymphocyte Postcapillary venule in the lymph node Postcapillary venule lymphocyte Cortex of the lymph node Subcapsular sinus of the lymph node Afferent lymphatic vessel Endothelial cell Valve Capsule Endothelial cell Lymphocyte Astroid Macrophage Endothelial cell Endothelial cell Reticular cell Lymphocyte Macrophage Subcapsular sinus of the lymph node Medulla of the lymph node Medullary cord Medullary sinus Trabecula LymphLymph circulationcirculation inin thethe lymphlymph nodenode LymphLymph circulationcirculation inin lymphlymph nodenode Afferent lymphatic vessels Subcapsular sinus Peritrabecular sinus Cortex lymphoid tissue Medullary sinus Efferent lymphatic vessels FunctionFunction ofof thethe lymphlymph nodenode FilterFilter lymphoidlymphoid fluidfluid ParticipateParticipate inin immuneimmune responseresponse ParticipateParticipate inin recirculationrecirculation ofof lymphocyteslymphocytes RecirculationRecirculation ofof lymphocyteslymphocytes Afferent lymphatic vessel Postcapillary venule Germinal center Medullary sinus Lymphocytes in Arteriole Efferent artery system lymphatic vessel LymphoidLymphoid organorgan CentralCentral lymphoidlymphoid organorgan ThymusThymus BoneBone marrowmarrow PeripheralPeripheral lymphoidlymphoid organorgan LymphLymph nodenode SpleenSpleen TonsilTonsil SpleenSpleen StructureStructure ofof thethe spleenspleen BloodBlood circulationcirculation ofof thethe spleenspleen FunctionFunction ofof thethe spleenspleen StructureStructure ofof thethe spleenspleen CapsuleCapsule ＆＆ trabeculatrabecula ParenchymaParenchyma WhiteWhite pulppulp PeriarterialPeriarterial lymphaticlymphatic sheathsheath SplenicSplenic corpusclecorpuscle MarginalMarginal zonezone RedRed pulppulp SplenicSplenic cordcord SplenicSplenic sinusoidsinusoid SpleenSpleen Trabecula White pulp Red pulp StructureStructure ofof thethe spleenspleen S: Splenic sinus SplenicSplenic corpusclecorpuscle Germinative center Central artery RedRed pulppulp ofof thethe spleenspleen RedRed pulppulp ofof thethe spleenspleen Splenic cord Splenic sinusoid RedRed pulppulp ofof thethe spleenspleen RedRed pulppulp ofof thethe spleenspleen M: Macrophage SplenicSplenic sinusoidsinusoid M: Macrophage SplenicSplenic sinusoidsinusoid 1. Endothelial cell 2. Red blood cell 3. Lymphocyte 4. Macrophage 5. Granulocyte 6. Reticular cell SpleenSpleen StructureStructure ofof thethe spleenspleen BloodBlood circulationcirculation ofof thethe spleenspleen FunctionFunction ofof thethe spleenspleen BloodBlood circulationcirculation ofof thethe spleenspleen S: Splenic sinus BloodBlood circulationcirculation ofof thethe spleenspleen Splenic arteries Trabecular arteries Central arteries Marginal zone sinuses Penicillar arteriole Splenic cord Splenic sinus Pulp venules Splenic vein Trabecula vein SpleenSpleen StructureStructure ofof thethe spleenspleen BloodBlood circulationcirculation ofof thethe spleenspleen FunctionFunction ofof thethe spleenspleen FunctionFunction ofof thethe spleenspleen BloodBlood filterfilter ImmunologicalImmunological