title: Analysis of human IL-2/IL-2 receptor beta chain interactions: monoclonal antibody H2-8 and new IL-2 mutants define the critical role of alpha helix-A of IL-2.
abstract: Interleukin 2 (IL-2) interacts with a receptor (IL-2R) composed of three subunits (IL-2R alpha, IL-2R beta and IL-2R gamma). IL-2R beta plays a critical role in signal transduction. An anti-human IL-2 mAb (H2-8) produced after immunization with peptide 1-30 of IL-2 was found to recognize the region occupied by Asp20, at the exposed interface between alpha-helices A and C. Muteins at position 17 and 20 are not recognized by mAb H2-8. mAb H2-8 specifically inhibits the IL-2 proliferation of TS1beta cells which are dependent on the expression of human IL-2R beta chain for IL-2 proliferation. Substitution at internal position Leu17 demonstrates that this position is essential for IL-2 binding and IL-2 bioactivity. New IL-2 mutants at position Asp20 have been analysed. Substitutions Asp --> Asn, Asp --> Lys, Asp --> Leu, show a correlation between diminished affinity for IL-2 receptor and reduced bioactivity measured on TS1beta cells. Mutein Asp Arg lose affinity for IL-2R and bioactivity simultaneously. Furthermore, during the course of the study we have found that mutein Asp20 --> Leu is an IL-2 antagonist. The biological effects of mAb H2-8 and the properties of new mutants at positions 17 and 20 demonstrate that this region of alpha helix-A is involved in IL-2-IL-2R beta interactions.
authors.affiliation: Immunogénétique Cellulaire, Institut Pasteur, Paris, France.
authors.forename: R
authors.initials: R
authors.lastname: Eckenberg
authors.forename: D
authors.initials: D
authors.lastname: Xu
authors.forename: J L
authors.initials: JL
authors.lastname: Moreau
authors.forename: M
authors.initials: M
authors.lastname: Bossus
authors.forename: J C
authors.initials: JC
authors.lastname: Mazie
authors.forename: A
authors.initials: A
authors.lastname: Tartar
authors.forename: X Y
authors.initials: XY
authors.lastname: Liu
authors.forename: P M
authors.initials: PM
authors.lastname: Alzari
authors.forename: J
authors.initials: J
authors.lastname: Bertoglio
authors.forename: J
authors.initials: J
authors.lastname: Theze
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001224:Aspartic Acid / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011485:Protein Binding; D017433:Protein Structure, Secondary; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D001224:Aspartic Acid; D004247:DNA; D007930:Leucine