T lymphocyte subsets, also known as T-cell subsets, refer to the different types of T lymphocytes or T cells found in the immune system. T lymphocytes are a type of white blood cell that play a vital role in the body's immune response against infections and diseases.
The immune system is composed of several specialized cells, including T lymphocytes, which are responsible for recognizing and targeting specific antigens or foreign substances in the body. T lymphocyte subsets are characterized based on the presence or absence of specific surface markers or proteins on their cell surface.
There are two major types of T lymphocyte subsets: CD4+ T cells and CD8+ T cells. CD4+ T cells, also known as helper T cells, play a crucial role in coordinating the immune response by activating other immune cells, such as B cells and macrophages. They are primarily involved in defending against intracellular pathogens, such as viruses.
CD8+ T cells, also called cytotoxic T cells or killer T cells, directly attack and destroy infected cells or cancerous cells. They recognize and bind to antigens presented on the surface of infected or abnormal cells, releasing toxic substances that induce cell death.
In addition to CD4+ and CD8+ T cells, there are other T lymphocyte subsets, including regulatory T cells (Treg), memory T cells, and natural killer T cells (NKT cells). Each subset has specific functions and contributes to the overall immune response.
Understanding the functions and characteristics of T lymphocyte subsets is essential in diagnosing and treating various immunological disorders, as imbalances or dysregulation of these subsets can lead to immune system dysfunction and diseases.
