A T cell-derived colony stimulating factor ("TC-CSF") may be isolated from media conditioned with T lymphocyte cells. TC-CSF stimulates formation of colonies composed of granulocytes, macrophages, megakaryocytes, fibrocytic stromal cells, lymphocytes, and mixed colonies of granulocytes and macrophages. Anion exchange chromatography may be employed in conjunction with gel filtration and rpHPLC to isolate TC-CSF. Human TC-CSF and murine TC-CSF cDNA, MRNA, genomic DNA nucleotide and amino acid sequences, expression products, pharmaceutical formulations and antibody materials are specifically provided.