title: A signaling-enhanced chimeric receptor to activate the ICOS pathway in T cells.
abstract: Activation of the inducible costimulator (ICOS) signaling pathway in T cells is difficult to assess with bioassays, because most T cell lines do not constitutively express ICOS. Additionally, engagement of ICOS by its natural ligand B7 related protein 1 (B7RP1) is insufficient to elicit ICOS signaling, but requires simultaneous costimulation of the T cell receptor (TCR) to be effective. Here we describe a genetically engineered human T cell line that expresses a chimeric receptor (ICOS-CD3) consisting of full-length human ICOS fused at its C-terminal end to the cytoplasmic domain of human CD3 zeta. When engaged by B7RP1, ICOS-CD3 initiated signaling independently of TCR costimulation and induced substantially more IL-2 secretion in Jurkat T cells compared to wildtype ICOS. We demonstrate that this signaling-enhanced chimeric receptor can be used in simple and sensitive bioassays to detect bioactive B7RP1, anti-B7RP1 drugs, and the presence of corresponding neutralizing anti-drug antibodies.
authors.affiliation: Clinical Immunology Group, Department of Bioanalytical Sciences/PKDM, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA. Electronic address: cvetterm@amgen.com.
authors.forename: Christian
authors.initials: C
authors.lastname: Vettermann
authors.affiliation: Clinical Immunology Group, Department of Bioanalytical Sciences/PKDM, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA.
authors.forename: Hannah P
authors.initials: HP
authors.lastname: Victor
authors.affiliation: Genome Analysis Unit, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Genome Analysis Unit, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA.
authors.forename: Cherylene
authors.initials: C
authors.lastname: Plewa
authors.affiliation: Clinical Immunology Group, Department of Bioanalytical Sciences/PKDM, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA.
authors.forename: Shalini
authors.initials: S
authors.lastname: Gupta
mesh_terms: D001681:Biological Assay / Q000379:methods; D017252:CD3 Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods; D015870:Gene Expression; D006801:Humans; D060945:Inducible T-Cell Co-Stimulator Ligand / Q000037:antagonists & inhibitors / Q000378:metabolism; D060889:Inducible T-Cell Co-Stimulator Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007376:Interleukin-2 / Q000096:biosynthesis; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
chemical_list: D017252:CD3 Complex; D060945:Inducible T-Cell Co-Stimulator Ligand; D060889:Inducible T-Cell Co-Stimulator Protein; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins
keywords: Bioactive drug assay; Bioassay; Biological characterization; Follicular T helper cells; Genetic fusion receptor; Lot release assay; NAb assay; Potency assay; Signaling; T cell activation