Which cells secrete IL-2?

Which cells secrete IL-2?

• A. Macrophages
• B. T cells
• C. B cells
• D. Endothelial cells

Answer: (B)

IL-2 is produced by activated T lymphocytes and serves as a growth factor for T cells. When a T cell recognizes its antigen with proper co-stimulation, it releases IL-2, which then acts on the same cell (autocrine) and neighboring T cells (paracrine) to drive clonal expansion and differentiation. This autocrine signaling loop is a hallmark of T-cell–mediated responses and is why the cells that secrete IL-2 are the T cells. Macrophages, B cells, and endothelial cells produce other cytokines (for example, macrophages release IL-1, IL-6, TNF-α; B cells produce antibodies and some cytokines; endothelial cells release factors like IL-8), not the main IL-2 growth factor.

IL-2 is produced by activated T lymphocytes and serves as a growth factor for T cells. When a T cell recognizes its antigen with proper co-stimulation, it releases IL-2, which then acts on the same cell (autocrine) and neighboring T cells (paracrine) to drive clonal expansion and differentiation. This autocrine signaling loop is a hallmark of T-cell–mediated responses and is why the cells that secrete IL-2 are the T cells. Macrophages, B cells, and endothelial cells produce other cytokines (for example, macrophages release IL-1, IL-6, TNF-α; B cells produce antibodies and some cytokines; endothelial cells release factors like IL-8), not the main IL-2 growth factor.