Recombinant human granulocyte colony stimulating factor: molecular and biological characterization

Human or rodent bone marrow treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in a CFU-GM assay yield predominantly granulocytic colonies. The specificity for granulocyte progenitors in vitro is also demonstrated in vivo by a five- to six-fold elevation in hamster peripheral blood neutrophils. Other cell types (monocytes, lymphocytes and eosinophils) remain stable. Analysis of mRNA from the bladder carcinoma cell line 5637 (1A6) shows the predominant species of mRNA codes for a mature protein of 174 amino acids. A small fraction of the mRNA can code for an alternative form of hG-CSF containing additional three amino acids between positions 35 and 36.