title: Synthesis and immunological activities of novel Toll-like receptor 7 and 8 agonists.
abstract: Single-stranded oligoribonucleotides (ORNs) stimulate innate immune responses through TLR7 and TLR8. Specific linkages and chemical modifications incorporated into synthetic ORN can greatly enhance nuclease stability, selectivity, and potency. In the present study, we have synthesized 15 ORN containing different sequence compositions and chemical modifications and studied their TLR7- and TLR8-mediated immune response profiles in HEK293 cells expressing human TLR7 or TLR8, human PBMCs, mDCs and pDCs, non-human primate (NHP) PBMCs, and in vivo in mice and NHPs. Based on the results obtained, eight of the ORNs containing specific chemical modifications induced immune responses through both TLR7 and TLR8, including activation of NF-κB in TLR7- and TLR8-transfected cell lines; induction of IFN-α, IL-6, TNF-α, IL-12, and IP-10 in human PBMCs; IFN-α induction in human pDCs; CD80 upregulation in human pDCs and mDCs; IL-12 induction following acute administration in mice; IFN-α, IP-10, IL-6, and IL-12 induction in NHP PBMCs; and IFN-α, IP-10, and IL-6 induction following acute administration in NHPs. Seven of the ORNs show selectivity for TLR8-induced responses; they specifically activate only TLR8-transfected cell lines, induce cytokines other than IFN-α in human and NHP PBMCs, activate mDCs more than pDCs, and do not induce IL-12 acutely in mice, consistent with the lack of functional TLR8 in mice. The novel TLR8-selective ORNs also induce cytokines other than IFN-α acutely in NHPs. In conclusion, we have designed and synthesized novel ORNs with varying sequence compositions and chemical modifications, which selectively act as agonists of TLR8 or dual agonists of TLR7 and TLR8.
authors.affiliation: Idera Pharmaceuticals, Inc., Cambridge, MA 02139, United States.
authors.forename: Ekambar R
authors.initials: ER
authors.lastname: Kandimalla
authors.forename: Mary
authors.initials: M
authors.lastname: Struthers
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Bett
authors.forename: Thomas
authors.initials: T
authors.lastname: Wisniewski
authors.forename: Sheri A
authors.initials: SA
authors.lastname: Dubey
authors.forename: Weiwen
authors.initials: W
authors.lastname: Jiang
authors.forename: Melissa
authors.initials: M
authors.lastname: Precopio
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Sun
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Lan
authors.forename: Sudhir
authors.initials: S
authors.lastname: Agrawal
authors.forename: Danilo R
authors.initials: DR
authors.lastname: Casimiro
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology; D015195:Drug Design; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007113:Immunity, Innate; D018664:Interleukin-12 / Q000096:biosynthesis; D008253:Macaca mulatta; D051379:Mice; D008810:Mice, Inbred C57BL; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000819:agonists / Q000235:genetics; D051199:Toll-Like Receptor 7 / Q000819:agonists* / Q000235:genetics; D051200:Toll-Like Receptor 8 / Q000819:agonists* / Q000235:genetics; D014162:Transfection
chemical_list: D016207:Cytokines; D009843:Oligoribonucleotides; D011994:Recombinant Proteins; C495348:TLR7 protein, human; C495349:TLR8 protein, human; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D018664:Interleukin-12