Production and characterization of human glioma cell-derived monocyte chemotactic factor

Since infiltration of monocytes into tumors may be mediated by tumor-derived chemoattractants, we characterized the monocyte-chemotactic activity (MCA) produced by glioma cell lines. The amount of MCA in the culture fluid of five lines tested differed by a factor of 25. U-105MG, the best producer, was selected for further study. After cells reached confluence and the medium was changed, MCA was detected by day 3 and remained at comparable levels on days 4 and 5. The molecular mass of MCA was approximately 17 kilodaltons, and the estimated isoelectric point ranged between pI 7 and pI 9. Because of the high constitutive production of MCA by U-105MG, sufficient material can be obtained for complete chemical characterization of this mediator of inflammation.