title: Deciphering the molecular bases of the biological effects of antibodies against Interleukin-2: a versatile platform for fine epitope mapping.
abstract: Elucidating the network of interactions established by Interleukin-2 is a key step to understanding its role as a master regulator of the immune system. Binding of this cytokine by specific antibodies gives rise to different classes of immune complexes that boost or inhibit immune responses. The molecular bases of such functional dichotomy are likely related to the nature of the recognized epitopes, making it necessary to perform fine epitope mapping studies. The current work was aimed at developing a versatile platform to do so. This was accomplished by display of human and mouse Interleukin-2 on filamentous phages, together with extensive mutagenesis of both antigens and high throughput screening of binding properties of more than 200 variants. Detailed molecular pictures of the epitopes were thus delineated for four antibodies against either human or mouse Interleukin-2, which refined and, in some cases, modified the conclusions derived from previous mapping studies with peptide libraries. Overlapping surface patches on mouse Interleukin-2 that also coincide with the predicted interface between the cytokine and its receptor alpha chain were shown to be recognized by two monoclonal antibodies that promote enhancement of immune responses, shedding new light on the structural bases of their biological activity. Our strategy was powerful enough to reveal multiple binding details and could be used to map the epitopes recognized by other antibodies and to explore additional interactions involving Interleukin-2 and related cytokines, thus contributing to our understanding of the complex structure-function relationships within the immune system.
authors.affiliation: Systems Biology Department, Center of Molecular Immunology, Calle 216 esq 15, Atabey, Playa, PO Box 16040, La Habana, CP 11600, Cuba. grojas@cim.sld.cu
authors.forename: Gertrudis
authors.initials: G
authors.lastname: Rojas
authors.forename: Amaury
authors.initials: A
authors.lastname: Pupo
authors.forename: Kalet
authors.initials: K
authors.lastname: Leon
authors.forename: Janet
authors.initials: J
authors.lastname: Avellanet
authors.forename: Tania
authors.initials: T
authors.lastname: Carmenate
authors.forename: Sachdev
authors.initials: S
authors.lastname: Sidhu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000378:metabolism; D000937:Antigen-Antibody Reactions / Q000235:genetics; D061505:Cell Surface Display Techniques; D018604:Epitope Mapping / Q000379:methods*; D000939:Epitopes / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D057166:High-Throughput Screening Assays; D006801:Humans; D056724:Immunity, Humoral / Q000235:genetics; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D013329:Structure-Activity Relationship
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007376:Interleukin-2; D010446:Peptide Fragments