The signaling molecule that regulates white blood cell formation and activation is called .

The signaling molecule that regulates white blood cell formation and activation is called cytokines.

Cytokines are a broad category of small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells. They act as signaling molecules that facilitate communication between cells, particularly in the immune response. Different types of cytokines include interleukins, interferons, and tumor necrosis factor (TNF), each playing unique roles in immune regulation. For instance, interleukin-2 (IL-2) is key in the proliferation of T cells, while other cytokines might promote the activation and differentiation of B cells, which produce antibodies.

Understanding the role of cytokines is essential not only for basic immunology but also for the development of therapies for various conditions, including autoimmune diseases, infections, and cancer, making them a significant area of study in medical research.