Disclosed is a newly identified secreted molecule, identified herein as “monocyte, granulocyte, and dendritic cell colony stimulating factor” (MGD-CSF), the polypeptide sequence, and polynucleotides encoding the polypeptide sequence. Also provided is a procedure for producing the polypeptide by recombinant techniques employing, for example, vectors and host cells. Additionally, procedures are described to modify the disclosed novel molecules of the invention to prepare fusion molecules. Also disclosed are methods for using the polypeptides and active fragments thereof for treatment of a variety of diseases, including, for example, cancer, autoimmune and inflammatory diseases, infectious diseases, and recurrent pregnancy loss.