02-components-of-the-immune-system

1、Chapter 2: the immune system----the immune organs,,Immune organsImmune cellsImmune molecules,Basic Components of the Immune System,Cells involved in immunity,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

2、,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,platelets,megakaryocyte,eosinophil,neutrophil,basophil,mast cell,common myeloid progenitor,,monocyte,macrophage,NaturalKiller cell,plasma c

3、ell,B Lymphocyte,T Lymphocyte,,common lymphoid progenitor,,,,,Pluripotent hematopoieticstem cell,,,B Lymphocyte,T Lymphocyte,,,humoral immunity,Produce antibody,cellular immunity,Help or monitor,The immune organs can b

4、e classified functionally into two main groups.The primary lymphoid organs provide appropriate microenvironments for the development and maturation of lymphocytes.The secondary lymphoid organs trap antigen from defi

5、ned tissues or vascular spaces and are sites where mature lymphocytes can interact effectively with that antigen.,Central lymphoid organs,Peripheral lymphoid organs,Immune organs,Section 1: Primary lymphoid organs,Thymu

6、s: The thymus is the site of T-cell development and maturation.Bursa: In birds , bursa is the site of B-cell origin and development. Bone marrow: In humans and mice, bone marrow is the site of B-cell origin and develop

7、ment.,In 1956, Bruce Glick and Timothy Chang reported:the bursa of Fabricius plays an important role in antibody production.,Jacques Miller found that removal of thymus (thymectomy) from mice resulted in fewer lymphocy

8、tes and no antibody to sheep red blood cells (1962). Later on, in thymectomized animals, the ability to reject allografts and to mount delayed hypersensitivity responses was drastically reduced.,,The place in which prol

9、iferation of HSC （haemopoietic stem cell，造血干細胞）takes place.The B lymphoid progenitor cells stay in BM and differentiate into mature B cells. Mature B cells leave BM and circulate in blood and tissue fluid. Plasma cells

10、 (B cells after antigen stimulation ) locate in BM to produce antibody.,Bone marrow,The T lymphoid progenitor cells generated in BM are transported by circulating blood to the thymus and differentiate into functional T c

11、ells.,The thymus,1. Cells: thymic stromal cells (TSC，胸腺基質(zhì)細胞) epithelial cells, monocytes/macrophage, thymic dendritic cells (TDC). thymocytes: T c

12、ells at different maturation stages2. Structure: cortex 皮質(zhì)---immature thymocytes medulla 髓質(zhì)---mature thymocytes MΦ, TDC3. Function:

13、 1) It is the site of T cell maturation/selection; 2) It determines the specificity of the TCR expressed on the T cells released to periphery.,,An old opinion: “the cemetery of lymphocytes”

14、 why???,抗原非依賴性分化,抗原依賴性分化,二級淋巴器官,前體T細胞,A nude mouse is a laboratory mouse from a strain with a genetic mutation that causes an absent thymusThe phenotype, or m

15、ain outward appearance of the mouse is a lack of body hair, which gives it the "nude" nicknameDue to the lack of thymus, function of T cells is greatly impairedDue to the malfunction of T cells, t

16、he humoral immunity and cell-mediated immunity are both decreased. WHY?? The nude mouse is valuable to research because it can receive many different types of tissue and tumor grafts, as it mounts no rejection

17、0;response.,Both the cortex and medulla of the thymus are crisscrossed by a three-dimensional stromal-cell network composed of epithelial cells, dendritic cells, and macrophages, which make up the framework of the organ

18、 and contribute to the growth and maturation of thymocytes.,T細胞由皮質(zhì)向髓質(zhì)遷移的過程也是T細胞由不成熟向成熟的發(fā)育過程。隨著細胞從皮質(zhì)層向髓質(zhì)的遷移，細胞也會逐漸變?yōu)槌墒斓腡細胞。,生理性胸腺萎縮,The thymus reaches its maximal size at puberty and then atrophies, with a significant dec

19、rease in both cortical and medullary cells and an increase in the total fat content of the organ.,Section 2: secondary lymphoid organs,Lymph nodes: lymph nodes are specialized for trapping antigen from local tissues (t

20、issue fluid).Spleen: the spleen specializes in filtering blood and trapping blood-borne antigens.Cutaneous-associated lymphoid systemmucosal-associated lymphoid tissue,[mju'kos?],Initiation of immune response,,,,

21、,,,,,,Right lymphotic duct,,,,,,,,,,,Cervical nodes,,,,,,,,,,,,Thoracic duct,,,,,thoracic duct,,,,,axillary,,,Cysterna chyli,,,,,,Paravertebralnodes,,,,,,,Inguinal nodes,,,,,,,,,,,,,,,lymphatic vessel,,,,,,,,,,,,,,,,,,,

22、,,,,,Lymph nodes are encapsulated structures that are strategically placed throughout the body to receive and filter antigens and cells from peripheral interstitial fluid and lymph. All lymph nodes eventually drain into

23、the thoracic duct and back to the peripheral blood.,Drains into left subclavian vein,Drains into right subclavian vein,The lymph node,Human: 2~10mm in diameterRound and kidney shapedConsists of : cortex (B-cell zone)

24、 paracortex (T-cell zone) central medulla (B-cell zone) other cells (macrophages, DC cells)4. The site of immune response to lymph-bo

25、rned antigens,Just like a filter,Segregation of T and B cells in different regions of peripheral lymphoid organs.The path by which naïve T and B cells migrate to different areas of a lymph node.Immunofluorescence

26、shows that the B cells and T cells locate in the follicles and in the parafollicular cortex, respectively.,High endothelial venule，HEV （ 高內(nèi)皮毛細血管后微靜脈）,HEV are specialized venules(小靜脈) found in lymphoid tissues. Lymphocyte

27、s migrate from blood into lymphoid tissues by attaching to and migrating across the high endothelial cells of the vessels.,,germinal center (B cells)1.The white pulp periart

28、eriolar lymphoid sheath (PALS, T cells) The red pulp (B cells) 2.Function: destroy the Ag, aged platelets, the site of immune response to

29、blood-borne antigens,The spleen,,,,,,,,白髓,紅髓,The spleen,,,Cutaneous and mucosal immune system皮膚和黏膜免疫系統(tǒng),1. Tonsil扁桃體, appendix闌尾, Peyer’s patches are mucosal lymphoid tissues.派氏集合淋巴組織2. B cell→IgA intraepithelial ly

30、mphocytes→Adaptive immunity 3. Function: cutaneous and mucosal lymphoid tissues are sites of immune responses to antigens that breach epithelia (or mucosal immunity).,,[kju’te?ni?s],皮膚的,1.Appendix of a 10 year old2.App

31、endix from a 36-year old man,A solitary 孤立的lymphoid nodule in the large intestine. This nodule is localized in the mucosa and submucosa of the intestinal wall.,Mucosal-associated lymphoid tissue (MALT),,,,,,,,,,,,,,,,,,,

32、,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Th,,,,,,IgA,sIgA,,,,,,,B,,,,,,help,M cell,Mucosal epithelium,Immune response in intestinal lymph system,Macrophage,Plasma cell,Lymphocytes and some monos can recirculate between l

33、ymphoid and non-lymphoid tissues. This helps lymphocytes to be exposed to the antigens which they recognize and is valuable for the distribution of effector cells to sites where they are needed.The recirculation is a c

34、omplex process depending on interactions between the cells of the immune response and other cell types such as endothelial cells. Naive lymphocytes move from the primary to secondary lymphoid tissue via the blood. Activ

35、ated lymphocytes move from the spleen, lymph nodes, and other lymphoid tissue (e.g., MALT) into the blood and then to other lymphoid and non-lymphoid tissues. Ag-presenting cells may carry Ag back to lymphoid tissues fro

36、m the periphery. The complex patterns of recirculation depend on the state of activation of the lymphocytes, the adhesion molecules expressed by endothelial cells, and the presence of chemotactic molecules, which selecti