EFFECTOR FUNCTIONS OF HELPER T-LYMPHOCYTES. Dendritic cells use several pathways to process and present protein antigens.

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 EffectorT 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.

ArmedEffector

T cell

CD28

Co-receptor

TcR

IL-2

Epithelialcell

NaïveT cell

Clonally selected,proliferating and

differentiatedT cell sees antigen on

a B7 negative cell

ArmedEffector

T cell

The effector programmeof the T cell is activatedwithout 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