title: Combinatorial contextualization of peptidic epitopes for enhanced cellular immunity.
abstract: Invocation of cellular immunity by epitopic peptides remains largely dependent on empirically developed protocols, such as interfusion of aluminum salts or emulsification using terpenoids and surfactants. To explore novel vaccine formulation, epitopic peptide motifs were co-programmed with structural motifs to produce artificial antigens using our "motif-programming" approach. As a proof of concept, we used an ovalbumin (OVA) system and prepared an artificial protein library by combinatorially polymerizing MHC class I and II sequences from OVA along with a sequence that tends to form secondary structures. The purified endotoxin-free proteins were then examined for their ability to activate OVA-specific T-cell hybridoma cells after being processed within dendritic cells. One clone, F37A (containing three MHC I and two MHC II OVA epitopes), possessed a greater ability to evoke cellular immunity than the native OVA or the other artificial antigens. The sensitivity profiles of drugs that interfered with the F37A uptake differed from those of the other artificial proteins and OVA, suggesting that alteration of the cross-presentation pathway is responsible for the enhanced immunogenicity. Moreover, F37A, but not an epitopic peptide, invoked cellular immunity when injected together with monophosphoryl lipid A (MPL), and retarded tumor growth in mice. Thus, an artificially synthesized protein antigen induced cellular immunity in vivo in the absence of incomplete Freund's adjuvant or aluminum salts. The method described here could be potentially used for developing vaccines for such intractable ailments as AIDS, malaria and cancer, ailments in which cellular immunity likely play a crucial role in prevention and treatment.
authors.affiliation: Department of Oncology, The Jikei University School of Medicine, Tokyo, Japan; Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ito
authors.affiliation: Department of Oncology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Eru
authors.initials: E
authors.lastname: Adachi
authors.affiliation: Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Tamiko
authors.initials: T
authors.lastname: Minamisawa
authors.affiliation: Department of Oncology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Sadamu
authors.initials: S
authors.lastname: Homma
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Koido
authors.affiliation: Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Shiba
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology; D049109:Cell Proliferation / Q000187:drug effects; D002999:Clone Cells; D020650:Combinatorial Chemistry Techniques; D045142:Cross-Priming / Q000187:drug effects / Q000276:immunology; D000939:Epitopes / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D007111:Immunity, Cellular / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010047:Ovalbumin / Q000276:immunology; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D011069:Poly I / Q000494:pharmacology; D011134:Polysaccharides / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D051117:Scavenger Receptors, Class A / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000939:Epitopes; D010455:Peptides; D011134:Polysaccharides; D051117:Scavenger Receptors, Class A; D011069:Poly I; D010047:Ovalbumin; C007789:fucoidan; D046988:Proteasome Endopeptidase Complex