title: Immunogenicity and safety of a DNA prime/adenovirus boost vaccine against rhesus CEA in nonhuman primates.
abstract: Scaling up experimental protocols from rodents to humans is often not a straightforward procedure, and this particularly applies to cancer vaccines, where vaccination technology must be especially effective to overcome a variety of immune suppressive mechanisms. DNA electroporation (DNA-EP) and adenoviral vectors (Ad) have shown high potency and therapeutic efficacy for different antigens in several pre-clinical models. To evaluate the ability of DNA-EP and Ad to break tolerance to a self-antigen in large animals, we have cloned the CEA homologue (rhCEA) from rhesus monkeys (Macaca mulatta) colon tissue samples. rhCEA is a 705 aa protein and shares 78.9% homology to human CEA protein. Immunogenicity of rhCEA expressing vectors was tested in mice and subsequently in rhesus monkeys. To further increase the immunogenic potency of these vectors, a synthetic codon optimized rhCEA cDNA (rhCEAopt) was constructed. Genetic vaccination of rhesus monkeys was effective in breaking immune tolerance to rhCEA in all immunized animals, maintaining over time the elicited immune response, and most importantly, neither autoimmunity nor other side-effects were observed upon treatment. Our data confirm the efficacy of genetic cancer vaccines in large animals such as nonhuman primates and show that development of modified expression cassettes that result in increased potency of plasmid DNA and adenovirus may have a significant impact on vaccine development against malignancies expressing tumor associated antigens in patients.
authors.affiliation: Istituto di Ricerche di Biologia Molecolare, Pomezia, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Aurisicchio
authors.forename: Carmela
authors.initials: C
authors.lastname: Mennuni
authors.forename: Patrizia
authors.initials: P
authors.lastname: Giannetti
authors.forename: Francesco
authors.initials: F
authors.lastname: Calvaruso
authors.forename: Maurizio
authors.initials: M
authors.lastname: Nuzzo
authors.forename: Barbara
authors.initials: B
authors.lastname: Cipriani
authors.forename: Fabio
authors.initials: F
authors.lastname: Palombo
authors.forename: Paolo
authors.initials: P
authors.lastname: Monaci
authors.forename: Gennaro
authors.initials: G
authors.lastname: Ciliberto
authors.forename: Nicola
authors.initials: N
authors.lastname: La Monica
mesh_terms: D000256:Adenoviridae / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019496:Cancer Vaccines / Q000276:immunology*; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D018274:Electroporation; D008253:Macaca mulatta; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D019496:Cancer Vaccines; D002272:Carcinoembryonic Antigen