Human monocyte chemoattractant protein-1 (hMCP-1) was produced using a baculovirus system. The hMCP-1 cDNA was inserted into the genomic DNA of Autographa californica nuclear polyhedrosis virus (AcNPV) using a transfer vector, pJVP10Z. Spodoptera frugiperda insect cells, which were infected with this recombinant virus, secreted recombinant hMCP-1 (re-hMCP-1) at the level of 10-20 micrograms/ml of culture medium. This product was shown to chemoattract monocytes. Three distinct bands of 11, 11.5 and 12 kDa were revealed by immunoblotting analysis, and this heterogeneity was assigned to differences in carbohydrate processing. N-terminal amino-acid sequence analysis of the purified product revealed identity with hMCP-1. Thus, in this system, re-hMCP-1 was produced in large quantities and modified in a manner similar to native hMCP-1.