title: Adjuvant activity of GP96 C-terminal domain towards Her2/neu DNA vaccine is fusion direction-dependent.
abstract: The Her2 is one of tumor-associated antigens (TAA), regarded as an ideal target of immunotherapy. DNA encoding full-length or truncated rat Her2/neu have shown protective and therapeutics potentials against Her2/neu-expressing mammary tumors. However, the efficacy of active vaccination is limited since Her2 is a self-tolerated antigen. Hence, new strategies are required to enhance both the quality and quantity of the immune response against Her2-expressing tumors. Many studies have used Her2/neu gene with cytokine or other molecules involved in regulation of immune response to enhance the potency of Her2/neu DNA vaccines. Some studies fused adjuvant gene to C-terminal domain of Her2/neu gene, while others fused the adjuvant gene N-terminally to Her2/neu gene, but no comparison on how direction of fusion could affect efficiency of DNA vaccine has ever been made. Based on previous reports demonstrating potent adjuvant activity of gp96 C-terminal domain, we chose it as adjuvant. The aim of this study was to investigate if direction of fusion could affect adjuvant activity of gp96 C-terminal domain or potency of Her2/neu DNA vaccination. To do so, we fused C-terminal domain of gp96 to downstream or C-terminal end of transmembrane and extracellular domain (TM+ECD) of rat Her2/neu and resultant immune response to DNA vaccination was evaluated. The results were compared with that of N-terminally fusion of gp96 C-terminal domain to TM+ECD of rat Her2/neu. Our results revealed that adjuvant activity of gp96 C-terminal domain is enhanced when fused N-terminally to TM+ECD of rat Her2/neu. It suggests that adjuvant activity of gp96 C-terminal domain towards Her2/neu is fusion direction-dependent.
authors: Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Ale-Ahmad Avenue, P.O. Box 14115-331, Tehran, Iran.
authors: Nafiseh
authors: N
authors: Pakravan
authors: Seyed Mahmoud
authors: SM
authors: Hashemi
authors: Zuhair Mohammad
authors: ZM
authors: Hassan
mesh_terms: D000276:Adjuvants, Immunologic / Q000235:genetics / Q000627:therapeutic use; D000818:Animals; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000235:genetics*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D019496:Cancer Vaccines / Q000235:genetics* / Q000276:immunology / Q000627:therapeutic use; D002460:Cell Line; D005260:Female; D050939:Gene Fusion; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D017434:Protein Structure, Tertiary; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D006360:Heat-Shock Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; C052646:sarcoma glycoprotein gp96 rejection antigens