Human Interleukin-2 And Its Monoclonal Antibodies: Biology And Applications

The cellular and molecular biology of human interleukin-2(IL-2) were studied systemiclly by using celullar and molecular biology techniques and a panel of anti-IL-2 monoclonal antibodies (McAb) with various biological characteristics were prepared. The laboratory and clinical applications of these antibodies and IL-2 were also investigated. The main works and results are as follows:1. The crucial techniques in establishing a stable assay system for detection of bioactivities of IL-2 were investigated. Firstly, difficuties in the freezing and recovery of IL-2-dependent cell lines were overcome. Secondly, an IL-2 assay using rat spleen lymphoblasts as indicator cells was established which has merits over the IL-2 assays using IL-2-dependent cell lines and mouse lymphoblasts.2. The cell biology and superinduction of IL-2 production by human tonsilar lymphocytes and Jurkat cell lines were studied. The maxium titer of superinduced IL-2 in the conditioned medium was above 3, 000 u/ml. The relationship between machanisms of superinduction to the IL-2 receptor expression was invesgated by using anti-IL-2 receptor McAb.3. Cloning of Jurkat cells and its promoting factors were studied. By 3 sequential subcloning of Jurkat cells, an IL-2 high-producer subline JurkatII-3 was established with stable and high level production activity of IL-2(3,000 u/ml).4. An expression plasmid for recombinant IL-2 was constructed by using PCR technique and high expression of rIL-2 in E.coli was achieved (30% of total bacterial protein).5. Methods suitable to hyperimmunization of unglycosylated recombinant lymphokines and low molecular weight peptides were established. A hyperimmunization method by using acid-treated bacteria as immunocarrier was used efficiently in preparing McAbs against IL-2 and its peptides .Stratiges to increase the number of the hybridomas secreting desined McAbs were proposed and met with success.6. Methods for rapid ranking and identifying the affinities of McAbs were studied and an affinity index was introduced , based on an absorption-elution ELISA, for rapid and proper choosing McAbs to be used either in detection assays or in affinity chromatographies.7. A panel of anti-IL-2 McAbs with different epitope specificities, affinitis and neutralizing activities were prepared. The McAbs with specificities to the C-terminus of IL-2 were also obtained. The reactions of the McAbs to the natural and recombinant IL-2 were damonstrated as well.8. A compitetion sandwich ELISA using anti-IL-2 McAbs and PolyAbs was devel-...