Abstract
We have developed a new IL-2 slow release system (IL-2 mini-pellet) using collagen from bovine Skin. Serum IL-2 activity after a single s. c. abministration of IL-2 mini-pellet, in which 1×106u of IL-2 was included, could be sustained until 72 hours. The activity of NK cells and cytotoxicity of LAK cells in the mouse spleen were effectively augmented after an administration of IL-2 mini-pellet. In histological study using monoclonal antibodies, a large number of Lyt-2 positive cells and L3T4 psitive cells were induced around the IL-2 mini-pellet. The adoptive immunotherapy by LAK cells and IL-2 mini-pellet showed a remarkable inhibition of lung metastasis and was more effectively than the adoptive immunotherapy by LAK cells and IL-2 in PBS. It is suggested that IL-2 mini-pellet is effective IL-2 slow release System in adoptive immunotherapy using LAK cells.
