MMI188 Lec 6 & 7

MMI188 Lec 6 & 7 - T Cell-Mediated Immunity...

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Unformatted text preview: T Cell-Mediated Immunity Lectures 6 and 11 Chapter 8 MMI 188 Human Immunology Jos V. Torres, Ph.D. Professor Medical Microbiology and Immunology School of Medicine University of California at Davis jvtorres@ucdavis.edu Activation of Nave T cells Meet specific antigen in secondary lymphoid tissues Undergo clonal expansion Differentiate into effector T cells Effector T cells migrate to sites of infection Antigen stimulates effector T cells to function Three Kinds of Effector T Cells: Cytotoxic CD8 T cells TH1 CD4 T cells TH2 CD4 T cells Activation of Nave T cells Meet specific antigen in secondary lymphoid tissues Undergo clonal expansion Differentiate into effector T cells Effector T cells migrate to sites of infection Antigen stimulates effector T cells to function Three Kinds of Effector T Cells: Cytotoxic CD8 T cells TH1 CD4 T cells TH2 CD4 T cells Naive T lymphocytes : T cells that have not yet been stimulated by antigen Recirculate through peripheral lymphoid organs- lymph nodes - L-selectin binds to ligand on high endothelial venules Express TCR, but do not engage in effector functions (cytokine production, cytolysis ) Effector T lymphocytes : T cells that have differentiated in response to antigen Perform functions required to eliminate pathogens/antigens - cytokine production (helper T cells) - cytolysis (cytotoxic T cells) Migrate to peripheral sites of infection or antigen entry Memory T lymphocytes : T cells that have differentiated in response to antigen - are long lived - are functionally silent Capable of mounting enhanced responses to antigen challenge Migrate to lymphoid tissues and peripheral sites of antigen entry Survive without antigen recognition Dendritic Cells pick up antigens in tissues migrate to peripheral lymphoid organs present antigens to nave T cells In Tissues: Immature DCs In Lymph Nodes: Mature or Activated DCs Dendritic Cells change functions after taking antigens from infected tissues to secondary lymphoid tissues. Dendritic cells use several pathways to process and present protein antigens Activation of Naive T Cells Antigen-presenting cells in secondary lymphoid tissues. Nave T cells enter from blood and lymph Homing of nave T cells to secondary lymphoid tissues cell surface molecules cell adhesion molecules Selectins Vascular addressins Integrins Immunoglobulin superfamily Main Players: L-selectin on nave T cell CD34 and GlyCAM-1 on high endothelial venules Nave T Cells Enter Lymph Nodes LFA-1 (integrin on T cell) ICAM-1 and -2 (immunoglobulin superfamily members on vascular endothelium) CCL21 (chemokine) Functions of T Cell Integrins Adhesion of T cells to APCs T cell activation Binding of T cells to endothelium T cell migration Ligands for integrins are induced on APCs and endothelial cells by inflammatory cytokines and microbes promote T cell responses to infectious agents...
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MMI188 Lec 6 & 7 - T Cell-Mediated Immunity...

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