We examined whether expression of monokine induced by IFN-γ (Mig, CXCL9) in tumors could produce antitumor effects. Murine lung carcinoma cells (A11) were retrovirally transduced with the murine Mig gene (A11/Mig) and were inoculated into syngeneic mice. Although proliferation in vitro of A11/Mig cells was not different from that of parent cells, the growth in vivo of A11/Mig tumors was significantly retarded compared with that of parent tumors. The antitumor effect was dependent on the amount of Mig produced. We compared the expression level of marker genes of lymphocytes and endothelial cells between parent and A11/Mig tumor masses with reverse transcription-polymerase chain reaction. Expression of CD4, CD8α, CD40, CD86, CD28, CD31 and vascular endothelial growth factor was not different between the two tumor groups but expression of CD40 ligand, CD80, NK1.1 and CXCR3 was relatively lower in A11/Mig tumors. Although Mig is a chemotactic factor for activated T and NK cells and an inhibitor for angiogenesis, the present data suggested that production of Mig in tumors did not recruit activated T and NK cells efficiently or suppress angiogenesis. The antitumor effects by Mig could be independent of anti-angiogenesis and recruitment of T and NK cells.

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