helper cell
Noun: A type of lymphocyte (white blood cell) that is a crucial part of the adaptive immune system. Specifically, it is a T cell that carries the CD4 receptor on its surface. Its primary function is to recognize foreign antigens presented by other immune cells and, in response, secrete chemical messengers called lymphokines (or cytokines). These lymphokines activate and direct the actions of other immune cells, such as B cells (which produce antibodies) and cytotoxic T cells (which kill infected cells).
The term is used in immunology, medicine, and biology to describe this specific coordinator cell of the immune response. * Helper cells are essential for mounting an effective defense against pathogens. * The virus targets and destroys helper cells, severely weakening the immune system. * Research focuses on how helper cells communicate with other components of the immune system.
- Helper T cell: This is the more precise and commonly used synonym. "Helper cell" in an immunological context is universally understood to mean "helper T cell."
- CD4+ T cell: This is a technical term referring to the same cell, named for the presence of the CD4 glycoprotein on its surface. It is often used in clinical contexts (e.g., monitoring HIV/AIDS).
- Helper T cell (n): The full and most accurate term.
- CD4 cell (n): A common abbreviation in medical contexts.
- T-helper cell (n): An alternate spelling.
- Regulatory T cell (Treg) (n): A different, related type of T cell that modulates or suppresses the immune response, acting as a counterbalance to helper T cells.
- Helper T lymphocyte
- CD4+ lymphocyte
- T-helper cell
In non-scientific, general language, "helper" can refer to any person or thing that provides assistance. However, the specific biological term "helper cell" almost exclusively refers to the immune cell defined above. The meaning is domain-specific to biology and medicine.
- T cell with CD4 receptor that recognizes antigens on the surface of a virus-infected cell and secretes lymphokines that stimulate B cells and killer T cells; helper T cells are infected and killed by the AIDS virus