GM-CSF, or Granulocyte-Macrophage Colony-Stimulating Factor, is a protein that plays a crucial role in the immune system. It is produced by various cells, including T cells, macrophages, and fibroblasts, and helps stimulate the production and function of white blood cells, particularly granulocytes and macrophages. These cells are essential for fighting infections and responding to inflammation. In medical research, GM-CSF is being studied for its potential therapeutic applications, including in cancer treatment and vaccine development. By enhancing the immune response, it may improve the effectiveness of certain therapies and help the body better combat diseases.