TAN-1511, its derivatives, production and use thereof

摘要

A compound of the formula: <IMAGE> wherein each R1, R2 and R3 is an aliphatic acyl group, X is an amino acid sequence consisting of 1 to 5 amino acid residues which contain at least one acidic amino acid residue, n is an integer of 0 to 4, provided that when n is 0, X has glutamyl-glycyl at its N-terminal and when n is 1 or 2, the acidic amino acid residue is an acidic amino acid residue other than D-glutamyl, or a salt thereof has an activity of remarkably improving anhematopoiesis and is useful as an immuno-stimulating agent having a leukocyte-increasing activity.