EFFECTOR FUNCTIONS OF HELPER T-LYMPHOCYTES

Dendritic cells use several pathways to process and present protein antigens

Co-stimulatory signals are required for the activation of naive T cells but not for the activation of effector T cells

Arming of effector T cells APC T Activation of NAÏVE T cells by Ag-mediated and co-stimulatory signals is not sufficient to trigger effector function, but….. IL-2 Effector T cell Clonal selection and differentiation How can this cell give help to or kill cells that express low levels of B7 family costimulators? the T cell will be activated to proliferate and differentiate under the control of autocrine IL-2 to an effector T cell. These T cells are ARMED.

Armed Effector T cell CD28 Co-receptor TcR IL-2 Epithelial cell Naïve T cell Clonally selected, proliferating and differentiated T cell sees antigen on a B7 negative cell Armed Effector T cell The effector programme of the T cell is activated without costimulation This contrasts the situation with naïve T cells, which are anergised without costimulation Effector function or anergy? cytokines

Phases of T cell responses Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Changes in surface molecules after T cell activation Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Sequence of events in the reactions of effector CD4+ T cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Properties of TH1, TH2, and TH17 subsets of CD4+ helper T cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Development of TH1, TH2, and TH17 subsets Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Development of TH1 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Functions of TH1 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Effector functions of Th1 cells Activation Killing Proliferation Feed back Entry to tissue Recruitment

Macrophage activation by TH1 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Classical and alternative macrophage activation Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Development of TH2 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Functions of TH2 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Th2 cells stimulate the proliferation and differentiation of naive B cells

Development of TH17 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Functions of TH17 cells Cellular and Molecular Immunology, 7th ed., 2014 Elservier

Functional classes of effector CD4 T cells