崔志刚20142015第一学期课件immune system.pptx

immune system;The lymphoid system protects the internal environment from invasion and damage by foreign substances. ; components: Lymphatic cells Lymphatic tissues Lymph organs (thymus, lymph node , and spleen) functions: immunologic defence immunologic homeostasis immunologic surveillance ;cell-mediated immunity It is mediated by specific T cells that destroy antigens. The process: A Tc cell recognize an antigen, Th cell release immune chemicals (cytokines), the cytokines stimulate Tc cell to destroy the antigen. Humoral immunity It is mediated by B cells. The specific antibodies bind to the antigens, forming an antigen- antibody complex. ;immune cells;T cells Differentiate in thymus Main surface receptor: TCR Encounter with antigen followed by proliferation Subdivided into Th, Tc, Ts and memory T cells ;B cells Differentiate mature in bone marrow Main surface receptor: sIgM Encounter with antigen followed by proliferation → plasma cells → Abs (Ig) → neutralize or inactivate antigens Some remain B cells called memory B cells ;NK cells Differentiate mature in bone marrow No T or B cell markers Attack virus-infected cancer cells without previous stimulation ;Summary;Antigen-presenting cells (APCs) General description A heterogeneous cell population including macrophages, dendritic cells Trap, process present antigens to T cells, (T cells can not recognize natural antigens) ;Dendritic cells Derived from bone marrow precursors Have dendritic processes;Mononuclear phagocyte system Definition System of cells in the body derived from bone marrow young monocytes with phagocytic activity Morphologic features Nucleus not lobated Abundant lysosomes in cytoplasm ;Components Macrophages in connective tissue, serous cavity, lymphoid tissues organs Monocytes in bone marrow blood Dust cells in lungs Kupffer cells in liver ;Lymphoid tissue;Lymphoid nodules Sphere in shape with various size Contain mainly B cells, and Th cells, macrophages When activated