title: A rapid fluorescence-based assay for classification of iNKT cell activating glycolipids.
abstract: Structural variants of α-galactosylceramide (αGC) that activate invariant natural killer T cells (iNKT cells) are being developed as potential immunomodulatory agents for a variety of applications. Identification of specific forms of these glycolipids that bias responses to favor production of proinflammatory vs anti-inflammatory cytokines is central to current efforts, but this goal has been hampered by the lack of in vitro screening assays that reliably predict the in vivo biological activity of these compounds. Here we describe a fluorescence-based assay to identify functionally distinct αGC analogues. Our assay is based on recent findings showing that presentation of glycolipid antigens by CD1d molecules localized to plasma membrane detergent-resistant microdomains (lipid rafts) is correlated with induction of interferon-γ secretion and Th1-biased cytokine responses. Using an assay that measures lipid raft residency of CD1d molecules loaded with αGC, we screened a library of ∼200 synthetic αGC analogues and identified 19 agonists with potential Th1-biasing activity. Analysis of a subset of these novel candidate Th1 type agonists in vivo in mice confirmed their ability to induce systemic cytokine responses consistent with a Th1 type bias. These results demonstrate the predictive value of this novel in vitro assay for assessing the in vivo functionality of glycolipid agonists and provide the basis for a relatively simple high-throughput assay for identification and functional classification of iNKT cell activating glycolipids.
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Pooja
authors.initials: P
authors.lastname: Arora
authors.forename: Manjunatha M
authors.initials: MM
authors.lastname: Venkataswamy
authors.forename: Andres
authors.initials: A
authors.lastname: Baena
authors.forename: Gabriel
authors.initials: G
authors.lastname: Bricard
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Natacha
authors.initials: N
authors.lastname: Veerapen
authors.forename: Rachel
authors.initials: R
authors.lastname: Ndonye
authors.forename: Jeong Ju
authors.initials: JJ
authors.lastname: Park
authors.forename: Ji Hyung
authors.initials: JH
authors.lastname: Lee
authors.forename: Kyung-Chang
authors.initials: KC
authors.lastname: Seo
authors.forename: Amy R
authors.initials: AR
authors.lastname: Howell
authors.forename: Young-Tae
authors.initials: YT
authors.lastname: Chang
authors.forename: Petr A
authors.initials: PA
authors.lastname: Illarionov
authors.forename: Gurdyal S
authors.initials: GS
authors.lastname: Besra
authors.forename: Sung-Kee
authors.initials: SK
authors.lastname: Chung
authors.forename: Steven A
authors.initials: SA
authors.lastname: Porcelli
mesh_terms: D000818:Animals; D002460:Cell Line; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005434:Flow Cytometry; D005699:Galactosylceramides / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D055611:Natural Killer T-Cells / Q000166:cytology* / Q000187:drug effects*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D005699:Galactosylceramides; C493154:alpha-galactosylceramide