Abstract
In a previous clinical study using a continuous infusion schedule of recombinant interleukin-2 (rIL-2) we noted a nearly complete loss of activity of EuroCetus rIL-2 when dissolved in 10 ml saline and infused at a very low rate through a plastic infusion device. In the present study, we demonstrated that the loss resulted from a concentration-dependent precipitation of rIL-2 in saline and adherence of the protein to the tubing material. These phenomena were not noted for four other rIL-2 muteins tested [Glaxo, Hoffmann-LaRoche, Amgen (2 muteins)]. EuroCetus rIL-2 was found to be completely soluble in water and 5% glucose.