The murine cells express two homologues of human MCP-1 βb-chemokine, which plays a crucial protective role in the early phase of immunological response against intracellular pathogens. We have found that the expression of mRNA for murine MCP-1/JE and MCP-5 CC-chemokines is upregulated in peritoneal exudate cells during Listeria infection. The MCP-5 mRNA expression was observed exclusively in the early stage of infection with both pathogenic and nonpathogenic Listeria strains. The upregulation of MCP-1/JE mRNA production depended on strain pathogenicity and increased gradually during four hours postinfection.