1、Chapter 2: the immune system-the immune organsImmune organsImmune cellsImmune moleculesBasic Components ofthe Immune System Cells involved in immunityplatelets megakaryocyte eosinophil neutrophil basophil mast cell common myeloid progenitor monocyte macrophage NaturalKiller cellplasma cell B Lymphoc
2、yteT Lymphocytecommon lymphoid progenitor Pluripotent hematopoieticstem cellB LymphocyteT Lymphocytehumoral immunity Produce antibody cellular immunity Help or monitor The immune organs can be classified functionally into two main groups. The primary lymphoid organs provide appropriate microenvironm
3、ents for the development and maturation of lymphocytes. The secondary lymphoid organs trap antigen from defined tissues or vascular spaces and are sites where mature lymphocytes can interact effectively with that antigen.Central lymphoid organsPeripheral lymphoid organsImmune organsSection 1: Primar
4、y lymphoid organs Thymus: 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 development.In 1956, Bruce Glick and Timothy Chang reported:the b
5、ursa of Fabricius plays an important role in antibody production. Jacques Miller found that removal of thymus (thymectomy) from mice resulted in fewer lymphocytes and no antibody to sheep red blood cells (1962). Later on, in thymectomized animals, the ability to reject allografts and to mount delaye
6、d hypersensitivity responses was drastically reduced.l The place in which proliferation of HSC （ haemopoietic stem cell，造血干细胞） takes place.l The B lymphoid progenitor cells stay in BM and differentiate into mature B cells. l Mature B cells leave BM and circulate in blood and tissue fluid. Plasma cel
7、ls (B cells after antigen stimulation ) locate in BM to produce antibody. Bone marrowl The T lymphoid progenitor cells generated in BM are transported by circulating blood to the thymus and differentiate into functional T cells.The thymus 1. Cells: thymic stromal cells (TSC，胸腺基质细胞 ) epithelial cells
8、, monocytes/macrophage, thymic dendritic cells (TDC).thymocytes: T cells at different maturation stages2. Structure: cortex 皮质皮质 -immature thymocytes medulla 髓质髓质 -mature thymocytesM, TDC3. Function: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”why?抗原非依赖性分化抗原依赖性分化二级淋巴器官前体 T细胞
