title: Complementary antitumor immunity induced by plasmid DNA encoding secreted and cytoplasmic human ErbB-2.
abstract: A plasmid DNA was constructed to encode the N-terminal 505 aa of human ErbB-2 (E2, HER-2/neu) and designated as secreted ErbB-2 (secE2). Recombinant secE2 protein was detected in the transfected cells and was secreted as an 80-kDa glycoprotein. Vaccination of BALB/c mice with secE2 DNA induced both IgG1 and IgG2a ErbB-2-specific Abs and protected approximately 90% of mice against mouse mammary tumor D2F2, which expressed human ErbB-2 (D2F2/E2). The efficacy of secE2 vaccine was comparable with that of wild-type ErbB-2 DNA, which encodes the entire 1258 aa of ErbB-2 protein, induced only IgG2a E2-specific Abs, and stimulated greater CTL activity. Immune lymphocytes were stimulated in vitro with irradiated 3T3 cells, which expressed ErbB-2, K(d), and B7.1. CTL activity was measured by the lysis of E2-positive target cells and by intracellular IFN-gamma production. To enhance CTL activation, mice were immunized with a combination of secE2 and cytoplasmic E2 (cytE2); the latter encodes the 1258-aa ErbB-2 protein that was released into the cytoplasm upon synthesis. Significant increase in CTL activity was demonstrated after mice were immunized with the combined vaccines and all mice were protected from D2F2/E2 tumor growth. Therefore, secE2, which induced Th2 Ab and weak CTL, conferred similar protection as E2, which induced Th1 Ab and strong CTL. Combined vaccination with secE2 and cytE2 resulted in Th2 Ab, strong CTL, and the most effective protection against tumor growth. The strategy of coimmunization with DNA that direct Ags to different subcellular compartments may be adapted as appropriate to optimize immune outcome.
authors.affiliation: Karmanos Cancer Institute, Departments of Otolaryngology, and Immunology and Microbiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Piechocki
authors.forename: S A
authors.initials: SA
authors.lastname: Pilon
authors.forename: W Z
authors.initials: WZ
authors.lastname: Wei
mesh_terms: D016475:3T3 Cells / Q000276:immunology; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D019496:Cancer Vaccines / Q000276:immunology*; D003593:Cytoplasm / Q000201:enzymology; D003602:Cytotoxicity, Immunologic; D004274:DNA, Recombinant / Q000235:genetics / Q000494:pharmacology; D005260:Female; D018734:Genes, erbB-2; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D007114:Immunization; D007074:Immunoglobulin G / Q000096:biosynthesis* / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D008325:Mammary Neoplasms, Experimental / Q000276:immunology / Q000517:prevention & control*; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000502:physiology; D009368:Neoplasm Transplantation; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D014162:Transfection; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D004274:DNA, Recombinant; D007074:Immunoglobulin G; D007371:Interferon-gamma; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic