A method using [3H]leucine-labeled granulocytes or macrophages for migration inhibition assay

The migration inhibitory activity of supernatants of Con A-Sepharose stimulated MNC cultures was tested by measuring the migration of [3H]leucine-labeled granulocytes or macrophages from agarose-containing capillary tube fragments. The migrated cells were harvested with an automated cell harvester on glass fiber filters and counted in a beta counter. Suspension of the target cells in agarose improves the accuracy of the method since migration from packed capillary tube fragments is sometimes not significantly different as between control and assay preparations. The concentration of agarose may inversely influence results, lower concentrations correlating with higher migration inhibition in the presence of assay supernatants. Different migration inhibition results are obtained when allogeneic granulocytes are used in parallel. For this reason a 10 times concentrated supernatant from a Con A-Sepharose-stimulated MNC culture, exhibiting the highest LIF activity at any mitogen concentration, was used as standard considered arbitrarily to contain 100 U. On the parallel regression lines of the dilution curves of the standard and assay preparations, reference with the standard is made at 25% migration inhibition as the comparison point.