IMMUNE SYSTEM Shiping Ding ( 丁世萍 ), Ph. D School of Medicine, Zhejiang University address:

Cells of the Immune System White Blood Cells Phagocytes - Neutrophils - Macrophages Lymphocytes Antigen-presenting cells –Macrophages - dendritic cell

Phagocytes Produced throughout life by the bone marrow. Scavengers – remove dead cells and microorganisms.

Lymphocytes Produce antibodies B-cells mature in bone marrow then concentrate in lymph nodes and spleen T-cells mature in thymus B and T cells mature then circulate in the blood and lymph Circulation ensures they come into contact with pathogens and each other

B-cells: become into plasma cell T-cells: cytotoxic T cell: Tc cell- kill the tumor cell, virus infective cell and foreign cell helper T cell: Th Cell- promotes activity of BLC and Tc Cell suppressor T cell: Ts Cell – regulate the function of BLC and TC

Antigen-presenting cells Antigen-presenting cells: dendritic cell: macrophage: mononuclear phagocytic system

Lymphoid organs a. Central lymphoid organs: thymus, bone marrow b. Peripheral lymphoid organs: lymph node, spleen and palatine tonsil

General organization of lymphoid organ: largely consist of lymphoid tissue Reticular tissue: stellate-shaped with processes to form network Diffuse lymphoid tissue Lymphoid nodules Cells: Lymphocyte (chiefly) Plasma cell antigen presenting cell other cells

a. Diffuse lymphoid tissue: no clear boundary mainly consists of T-lymphocyte postcapillary venules:postcapillary venules: -high endothelial venules, lining of tall cuboidal cells -opening for lymphocyte enter lymphoid tissue from blood Diffuse LT Lymphoid nodule

b. Lymphoid nodule: spherical or ovoid have clear boundaries mainly composed of B- lymphocyte germinal center: lighter- stained central zone, these cells produce antibody- synthesizing plasma cells

Lymphatic organs: central lymphatic organs: produce the lymphocyte antigen-independent proliferation contain: thymus---T-lymphocyte bone marrow---B-lymphocyte peripheral lymphatic organs: receive the lymphocyte and perform the immune response antigen-dependent proliferation contain: lymph node spleen tonsils

The immune system: consists of the lymphatic organs, lymphocytes of the blood and lymph, and collections of different types of lymphocytes dispersed throughout the connective tissue. consists of the lymphatic organs, lymphocytes of the blood and lymph, and collections of different types of lymphocytes dispersed throughout the connective tissue. is essential to the body’s immunological defense against bacteria, viruses and other foreign bodies. is essential to the body’s immunological defense against bacteria, viruses and other foreign bodies. Immune response: Cellular immunity: involving mainly T-lymphocytesCellular immunity: involving mainly T-lymphocytes Humoral immunity: involving mainly B-lymphocytesHumoral immunity: involving mainly B-lymphocytes Mast cells, macrophages and other white blood cells are also involved in the immune response.Mast cells, macrophages and other white blood cells are also involved in the immune response.

Good-bye!