Monoclonal antibodies against unglycosylated recombinant interleukin 2

We report the characterization of two monoclonal antibodies (mab) directed against unglycosylated human IL2. Mice were immunized with recombinant IL2 (rIL2) and two of the hybridomas obtained (referred to as 15.2 and 17.2) were selected for further analysis. Both 15.2 and 17.2 antibodies bound to recombinant IL2 and weakly to natural IL2 in an enzyme linked immuno assay (ELISA). Both antibodies were very efficient in retaining rIL2 on affinity columns with a yield of 95% purified material after acid elution. In high concentrations both mabs strongly inhibited the growth of CTLL-2 cells induced by the immunizing-rIL2, while the growth of CTLL-2 cells in the presence of natural-IL2 was only slightly inhibited. Neither mab blocked the effect of rat IL2 in this test. Both mabs were used in an immuno-radiometric assay (IRMA) to quantify recombinant IL2. Cross inhibition experiments performed in this last assay indicate that the two mabs recognize two different epitopes on the recombinant IL2 molecule.