title: Structure-guided development of a high-affinity human Programmed Cell Death-1: Implications for tumor immunotherapy.
abstract: Programmed Cell Death-1 (PD-1) is an inhibitory immune receptor, which plays critical roles in T cell co-inhibition and exhaustion upon binding to its ligands PD-L1 and PD-L2. We report the crystal structure of the human PD-1 ectodomain and the mapping of the PD-1 binding interface. Mutagenesis studies confirmed the crystallographic interface, and resulted in mutant PD-1 receptors with altered affinity and ligand-specificity. In particular, a high-affinity mutant PD-1 (HA PD-1) exhibited 45 and 30-fold increase in binding to PD-L1 and PD-L2, respectively, due to slower dissociation rates. This mutant (A132L) was used to engineer a soluble chimeric Ig fusion protein for cell-based and in vivo studies. HA PD-1 Ig showed enhanced binding to human dendritic cells, and increased T cell proliferation and cytokine production in a mixed lymphocyte reaction (MLR) assay. Moreover, in an experimental model of murine Lewis lung carcinoma, HA PD-1 Ig treatment synergized with radiation therapy to decrease local and metastatic tumor burden, as well as in the establishment of immunological memory responses. Our studies highlight the value of structural considerations in guiding the design of a high-affinity chimeric PD-1 Ig fusion protein with robust immune modulatory properties, and underscore the power of combination therapies to selectively manipulate the PD-1 pathway for tumor immunotherapy.
authors.affiliation: Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Eszter
authors.initials: E
authors.lastname: Lázár-Molnár
authors.affiliation: Department of Radiation Oncology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Scandiuzzi
authors.affiliation: Department of Radiation Oncology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Indranil
authors.initials: I
authors.lastname: Basu
authors.affiliation: Department of Radiation Oncology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Quinn
authors.affiliation: Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Eliezer
authors.initials: E
authors.lastname: Sylvestre
authors.affiliation: Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Edith
authors.initials: E
authors.lastname: Palmieri
authors.affiliation: Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Udupi A
authors.initials: UA
authors.lastname: Ramagopal
authors.affiliation: Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA; Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
authors.forename: Stanley G
authors.initials: SG
authors.lastname: Nathenson
authors.affiliation: Department of Radiation Oncology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA; Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA. Electronic address: cguhamd@gmail.com.
authors.forename: Chandan
authors.initials: C
authors.lastname: Guha
authors.affiliation: Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA; Department of Physiology & Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA. Electronic address: steve.almo@einstein.yu.edu.
authors.forename: Steven C
authors.initials: SC
authors.lastname: Almo
mesh_terms: D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000628:therapy*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000378:metabolism; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics / Q000276:immunology; D007156:Immunologic Memory; D007167:Immunotherapy / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D061026:Programmed Cell Death 1 Receptor / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding; D000072417:Protein Domains; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D016207:Cytokines; D007136:Immunoglobulins; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; D011993:Recombinant Fusion Proteins
keywords: High-affinity mutant; Immunotherapy; PD-1; PD-1 Ig fusion protein; Radio-immunotherapy