Pure peptide products, derived from either human glioma cell line U-105MG or human peripheral blood mononuclear leukocytes are provided; the products have a molecular mass of about 8,400 daltons, and the products exhibit optimal monocyte chemotactic activity at a concentration of 1 nM. The cloning of full length cDNA for the peptide products is also provided, as well as recombinant methods for the production of monocyte chemoattractant products. Methods of treating infection and neoplasms in a human body with such peptides and monocyte chemoattractant products are additionally provided, as well as pharmaceutical compositions for the same.