What is the major effector function of CD8 cytotoxic T cells?
CD8+ T cells mediate their effector functions through production of cytokines such as IFN-γ and tumor necrosis factor (TNF)-α and/or by cytolytic mechanisms.
What do CD8 cells respond to?
CD8 T cells mediate viral clearance by utilizing a variety of effector mechanisms to induce the apoptosis of virus-infected cells (95). CD8 T cells can use direct cell–cell contact to eliminate target cells through the interactions of surface molecules such as Fas (CD95) and FasL (CD95L).
Why do CD8 T cells need CD4 T cells?
CD4+ T cell help promotes the induction of tissue-resident memory CD8+ T cells during mucosal infection through guidance of CD8+ T cells into a microenvironment where they can become exposed to the signals necessary for their continued maintenance within the tissue.
How do CD4 T cells activate CD8 T cells?
Once the naïve CD8+ T cell is bound to the infected cell, the infected cell is triggered to release CD40. This CD40 release, with the aid of helper T cells, will trigger differentiation of the naïve CD8+ T cells to mature CD8+ T cells.
Do CD8 cells release cytokines?
CD8+ cells exert their effects mainly by two mechanisms, cytolytic attack on target cells or secretion of interleukins and cytokines. CD8+ cells also release a number of cytokines such as IFNγ, TNFα, and IL-2 as well as many chemokines, which can promote recruitment of other cells to sites of infection.
Why is CD8 important?
CD8+ T cells (often called cytotoxic T lymphocytes, or CTLs) are very important for immune defence against intracellular pathogens, including viruses and bacteria, and for tumour surveillance.
Can CD8 work without CD4?
Although the primary CD8 T cell response to infections can be independent of CD4 T cell help, recent studies have indicated that CD4 T cell help is required for the generation of long-lived, functional memory CD8 T cells that respond rapidly upon secondary exposure to pathogens (23, 24, 25).