Identification of structural differences between different forms of interleukin-2 (IL-2) using anti-(human recombinant) IL-2 monoclonal antibodies

• Published in: Cytokine (Philadelphia, Pa.) Vol. 3; no. 1; pp. 54 - 59
• Main Authors: Mevissen, Marcel L.C.M., de Boer, Mark, Tuin, Kees, Tager, Joseph M., de Groot, Cornelis
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 1991
• Subjects: Animals; Antibodies, Monoclonal; Antibody Specificity; Antigen-Antibody Complex; Cell Line; Epitopes - analysis; Female; Humans; IL-2; Interleukin-2 - immunology; Interleukin-2 - pharmacology; Kinetics; Lymphocyte Activation - drug effects; Mice; Mice, Inbred BALB C - immunology; monoclonal antibodies; Recombinant Proteins - immunology; Recombinant Proteins - pharmacology; structural differences; T-Lymphocytes, Cytotoxic - drug effects; T-Lymphocytes, Cytotoxic - immunology; structural differences; IL-2; monoclonal antibodies
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1016/1043-4666(91)90010-B

We have generated a panel of murine monoclonal antibodies (mAbs) directed against recombinant human interleukin-2 (rh IL-2). All mAbs have similar affinities (K aff ≅ 10 −8 M) and are of the IgG 1 isotype. Specificity of the mAbs has been established using an ELISA method and immunoprecipitation of native human interleukin-2 (nh IL-2) present in supernatants from PHA-stimulated human mononuclear cells (PBMNC). Four of the nine mAbs inhibit the rh IL-2-dependent proliferation of a murine cytotoxic T-lymphocyte line (CTLL-2). The estimated ID 50, in the presence of 0.75 IU rh IL-2/ml, ranges from 2.0 μg/ml to 30 μg/ml final concentrations of the antibodies. Using different forms of IL-2 we found that the mAbs give different patterns of inhibition of the IL-2-dependent proliferation. One mAb (AMCIB 27) is able to discriminate between rh and nh IL-2. Findings with another mAb (AMCIB 24) indicate that possible functional differences between human IL-2 and recombinant murine (rm) IL-2 are caused by differences in the active sites. The results of this investigation show that it is possible to obtain mAbs, after immunization with rh IL-2, that differ in their ability to inhibit the biological action of different forms of IL-2.