The<unk><unk>  factor 1 <unk> , also known as<unk>  <unk> , is a secreted cytokine which causes hematopoietic stem cells to differentiate into macrophages or other related cell types. Eukaryotic cells also produce<unk>  in order to combat intercellular viral infection. It is one of the three experimentally described<unk><unk>  factors.<unk>  binds to the<unk><unk>  factor 1 receptor. It may also be involved in development of the placenta.
Macrophage colony-stimulating factor
Macrophage-activating factor
Leukemia inhibitory factor
Hemopoietic growth factor
Thymic stromal lymphopoietin
Interleukin
Major basic protein
Tumor necrosis factor