helper T cell
Noun: A type of white blood cell (lymphocyte) that plays a central role in the adaptive immune system. Specifically, it is a T cell that carries the CD4 receptor on its surface. Its primary functions are to recognize antigens presented by other cells and to coordinate the immune response by secreting signaling proteins called lymphokines (or cytokines). These signals activate and direct other immune cells, including B cells (which produce antibodies) and cytotoxic T cells (which kill infected cells). This cell type is a primary target of the Human Immunodeficiency Virus (HIV), which leads to Acquired Immunodeficiency Syndrome (AIDS).
The term is used in immunology, medicine, and biology to describe this specific component of the immune system. * Helper T cells are essential for mounting an effective defense against pathogens. * A low count of helper T cells is a key indicator of HIV progression. * The research focused on how the vaccine activates helper T cells.
- Helper T cell subset/type: Refers to specialized categories of helper T cells, such as Th1, Th2, and Th17 cells, each secreting different cytokines to combat specific types of threats (e.g., intracellular parasites, extracellular parasites, fungal infections).
- CD4+ T cell: A common synonym in scientific literature, emphasizing the presence of the CD4 surface protein.
- T-helper cell: An alternative spelling with the same meaning.
- CD4 cell: A broader term that includes helper T cells but may also refer to other immune cell types expressing the CD4 protein.
- T lymphocyte / T cell: The general category of white blood cells that includes helper T cells, cytotoxic T cells, and regulatory T cells.
- Lymphokine: A type of cytokine secreted by lymphocytes, such as helper T cells.
- CD4+ T cell
- T-helper cell
- CD4 lymphocyte
- Helper lymphocyte
- Cell-mediated immunity: The aspect of the immune response coordinated by T cells, in which helper T cells play a directing role.
- Humoral immunity: The aspect of the immune response involving antibody production by B cells, which is activated by helper T cells.
- Antigen presentation: The process by which other cells display antigen fragments to helper T cells, which is necessary for their activation.
- 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