title: Synthesis and in vitro characterization of antigen-conjugated polysaccharide as a CpG DNA carrier.
abstract: Oligodeoxynucleotides containing unmethylated CpG sequences (CpG DNAs) are known as an immune adjuvant. CpG DNAs coupled with a particular antigen enabling both CpG DNA and antigen delivery to the same antigen-presenting cell have been shown to be more effective. Based on our previous finding that beta-(1-->3)-D-glucan schizophyllan (SPG) can be used as a CpG DNA carrier, here we present the synthesis of an antigen-conjugated SPG and the characterization of the conjugate. Ovalbumin (OVA, 43 kDa) was used as a model antigen, and two OVA were conjugated to one SPG molecule (M(w) = 150,000), denoted by OVA-SPG. Circular dichroism and gel electrophoresis showed that OVA-SPG could form a complex with a (dA)(40)-tailed CpG DNA at the 3' end (1,668-(dA)(40)). When OVA-SPG was added to macrophages (J774.A1), the amount of the ingested OVA-SPG was increased compared with that of OVA itself, suggesting that Dectin-1 (proinflammatory nonopsonic receptor for beta-glucans) is involved to ingest OVA-SPG. Furthermore, the complex of the conjugate and DNA was co-localized in the same vesicles, implying that OVA (antigen) and CpG DNA (adjuvant) were ingested into the cell at the same time. This paper shows that OVA-SPG can be used as a CpG DNA carrier to induce antigen-specific immune responses.
authors.affiliation: Department of Chemical Processes & Environments, The University of Kitakyushu, 1-1, Hibikino, Fukuoka 808-0135, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Shimada
authors.forename: Ken J
authors.initials: KJ
authors.lastname: Ishii
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takeda
authors.forename: Cevayir
authors.initials: C
authors.lastname: Coban
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Torii
authors.forename: Seiji
authors.initials: S
authors.lastname: Shinkai
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sakurai
mesh_terms: D000276:Adjuvants, Immunologic / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002942:Circular Dichroism; D018899:CpG Islands / Q000276:immunology*; D046911:Macromolecular Substances; D008958:Models, Molecular; D010047:Ovalbumin / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D012566:Sizofiran / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D046911:Macromolecular Substances; D012566:Sizofiran; D010047:Ovalbumin