A white blood cell (lymphocyte) that helps to protect the body against foreign materials or organisms.
A type of T lymphocyte, whose surface is marked by CD4 receptors, that is involved in both cell-mediated and antibody-mediated immune responses. It secretes cytokines (chemical signals) that stimulate the activity of B cells and other T cells and binds with class II histocompatibility antigens, which are processed by macrophages and other antigen-presenting cells.
Also known as CD4 cells; lymphocytic cells that are components of the adaptive immune system that direct and amplify the immune response through the use of chemical messengers.
A vital cellular constituent of the immune system, recognized for its significant role in eliminating bacteria and viruses from the body, is distinguished by the presence of the CD4 protein on its surface. This type of cell is associated with uncontrolled division in Cutaneous T-cell Lymphoma (CTCL).