T-cells

T cells or T lymphocytes are a type of white blood cell that play a central role in cell-mediated immunity. They are named after the thymus, an organ where T cells mature. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor on the cell surface.

Types of T cells

There are several different types of T cells, each with a unique function:

• Helper T cells assist other white blood cells in immunologic processes, including maturation of B cells into plasma cells and memory B cells, and activation of cytotoxic T cells and macrophages.
• Cytotoxic T cells destroy virus-infected cells and tumor cells, and are also implicated in transplant rejection.
• Memory T cells remain long-term after an infection has resolved, and quickly expand to large numbers of effector T cells upon re-exposure to their cognate antigen, thus providing the immune system with "memory" against past infections.
• Regulatory T cells are crucial for the maintenance of immunological tolerance. Their major role is to shut down T cell-mediated immunity toward the end of an immune reaction and to suppress auto-reactive T cells that escaped the process of negative selection in the thymus.

Function

T cells are involved in cell-mediated immunity, one of the two primary forms of adaptive immunity. They can distinguish between self and non-self cells by recognizing antigenic peptides presented on the cell surface. In response to an intruder, T cells trigger the immune response and direct other cells to attack and destroy the invading cell.

Clinical significance

T cells play a crucial role in the immune response to various diseases. For example, in HIV infection, the virus primarily targets helper T cells, leading to a significant decrease in the body's ability to fight off infection. In autoimmune diseases like rheumatoid arthritis and type 1 diabetes, T cells mistakenly attack the body's own cells, causing inflammation and tissue damage.

T-cells Resources
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