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In 1991, three groups reported discovering CD154, which is the molecular basis of T cell helper function. Seth Lederman at Columbia University generated a murine monoclonal antibody, 5c8 that inhibited contact-dependent T cell helper function in human cells which characterized the 32 kDa surface protein transiently expressed on CD4 + T cells. [16]
T cells are grouped into a series of subsets based on their function. CD4 and CD8 T cells are selected in the thymus, but undergo further differentiation in the periphery to specialized cells which have different functions. T cell subsets were initially defined by function, but also have associated gene or protein expression patterns.
Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces, antigen processing must occur before the antigen fragment can be recognized by a T-cell receptor.
The activation of a naive helper T-cell causes it to release cytokines, which influences the activity of many cell types, including the APC (Antigen-Presenting Cell) that activated it. Helper T-cells require a much milder activation stimulus than cytotoxic T cells. Helper T cells can provide extra signals that "help" activate cytotoxic cells. [6]
CD4+ T helper cells are white blood cells that are an essential part of the human immune system. They are often referred to as CD4 cells, T helper cells or T4 cells. They are called helper cells because one of their main roles is to send signals to other types of immune cells, including CD8 killer cells, which then destroy the infectious ...
Antigen presentation stimulates immature T cells to become either mature "cytotoxic" CD8+ cells or mature "helper" CD4+ cells. An antigen-presenting cell (APC) or accessory cell is a cell that displays an antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation.
A third category called T helper 17 cells (T H 17) were also discovered which are named after their secretion of Interleukin 17. CD8 + cytotoxic T-cells may also be categorized as: [5] T c 1 cells, T c 2 cells. Similarly to CD4 + T H cells, a third category called T C 17 were discovered that also secrete IL-17.
Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells.. A cytotoxic T cell (also known as T C, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8 + T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected by intracellular pathogens such as viruses or bacteria, or ...