【病毒外文文献】2005 978_ Production of SARS Coronavirus-Like Particles That Bind Host Cells and Serve as Vaccine Antigen

Molecular Therapy Volume 11 Supplement 1 May 2005 Copyright The American Society of Gene Therapy S378 GENE THERAPY FOR INFECTIONS AND VACCINES 978 Production of SARS Coronavirus Like Particles That Bind Host Cells and Serve as Vaccine Antigen Yi Chun Yeh 1 En Hau Lin 1 Chang Jen Huang 2 Ning Sun Yang 1 Pei Wen Hsiao 1 1 Institute of BioAgricultural Science Academia Sinica Taipei Taiwan 2 Institute of Biochemistry Academia Sinica Taipei Taiwan Severe Acute Respiratory Syndrome SARS is a deadly form of pneumonia caused by a recently identified coronavirus SARS CoV Viral particles of SARS CoV comprise three viron structural proteins including spike S membrane M and envelope E To efficiently express S M and E proteins of SARS CoV simultaneously in one cell we constructed a plasmid harboring the three genes with GFP green fluorescence protein fusion to the M protein Expression of the three genes is engineered under regulation of tet operon Stable transfection of this plasmid into Vero E6 cells creates cell lines showing inducible expression of virus like particles VLPs Expression and packaging of VLP in cytoplasm is observed by confocal microscopy We then purified the secreted VLPs from cell culture medium through ultra centrifugation Containment of each protein in VLPs was assured by coomassie blue staining and western blotting Interestingly two types of particles were secreted by one of our producing cell lines One contains M dominantly the other contains S dominantly Electron microscopy reveals homogenous particles of both VLPs We have further demonstrated binding capability of M dominant VLP to Vero E6 cells as host by flow cytometry and confocal microscopy analyses Immunization of the two VLPs induced antibodies against both VLPs in ELISA and western blot suggesting a promising immunogenicity of both VLPs as vaccine antigen The genetic engineered VLPs bearing resemblance to the authentic SARS CoV as well as their antibodies are important tools toward development of effective vaccine against highly contingent infectious disease like SARS 979 Antigen Transduced T Cell Blasts Specifically Delete Antigen Specific Cytotoxic T Cells and Induce a CD4 CD25 Regulatory T Cell Response Aaron E Foster 1 Takayuki Okamura 1 Cliona M Rooney 1 1 Center for Cell and Gene Therapy Baylor College of Medicine The Methodist Hospital and Texas Children s Hospital Houston TX Introduction Antigen presentation by T cells has been shown to induce anergy and apoptosis in responding antigen specific T cells This phenomenon might be useful in targeting antigen specific T cells for the treatment of autoimmune disease and allogeneic organ transplantation Therefore we examined the immune response to antigen presenting T cell blasts T APC transduced with known antigens CMV pp65 EBV LMP2 or adenovirus hexon protein Methods T APC were prepared by stimulating PBMC on OKT3 and anti CD28 coated plates and transducing with the MSCV retroviral vector encoding CMVpp65 EBV LMP2 or adenovirus hexon protein T APC were subsequently expanded with high dose IL 2 PBMC were then stimulated on a weekly basis with irradiated antigen expressing autologous T APC Responding cells were analyzed using MHC class I multimers for pp65 LMP2 and hexon proteins annexin V and antibodies to CD4 CD8 CTLA4 GITR and LAG 3 by flow cytometry Analysis of FoxP3 expression was performed using real time quantitative PCR Q PCR normalized to GAPDH To test regulatory activity responder cells cultures were separated into CD4 CD25 and CD4 CD25 populations and examined for their ability to inhibit proliferation of PBMC against pp65 or LMP2 transduced EBV lymphoblastoid B cell lines LCL in secondary co culture experiments Results T APC were readily expanded 100 fold and transduced by retroviral constructs 90 GFP Antigen transduced T APC were capable of stimulating an antigen specific CD8 T cell response as evident by a temporary increase in the frequency of pp65 LMP2 and hexon specific T cells when analyzed by multimers However the frequencies of responding antigen specific CD8 T cells decreased during multiple T APC stimulations 7 to 21 days and were positive for annexin V indicating apoptosis This effect could not be rescued by restimulation with antigen transduced professional APCs such as EBV LCL T APC stimulated cultures n 23 showed a significant increase in the frequency of CD4 CD25 T cells that were FoxP3 CTLA4 GITR and LAG 3 positive when compared to LCL n 10 stimulated cultures P 05 CD4 CD25 T cells inhibited up to 95 inhibition secondary cultures stimulated with LCL in a cell contact dependent manner indicating a potential regulatory function Conclusions T APC transduced with antigen induced antigen specific anergy apoptosis in CD8 T cells and an increase in CD4 CD25 regulatory T cells in vitro Vaccination with T APC expressing auto immune antigens may be useful in targeting auto reactive T cells and inducing regulatory T cells in diseases such as multiple sclerosis or type I diabetes 980 Specific Immune Response Against the Plasmodium falciparum CS Protein Mediated by Baculovirus Vectors Robert Strauss 1 Andreas H ser 3 Nelson Di Paolo 1 Andre Lieber 1 2 Christian Hofmann 4 1 Department of Medicine University of Washington Seattle WA 2 Department of Pathology University of Washington Seattle WA 3 3Clinical Research AG Berlin Germany 4 APIT Laboratories GmbH Potsdam Germany Malaria is the most common tropical disease worldwide More than 300 million people are infected and about 2 3 million die annually The most pathogenic form Malaria tropica is caused by Plasmodium falciparum This enormous world health problem is compounded by parasites becoming resistant to drugs which are commonly used for treatment and also the complete lack of an effective vaccine Recombinant baculovirus vectors derived from the Autographa californica nuclear polyhedrosis virus AcNPV are commonly used as a tool for high level expression of recombinant proteins of interest in insect cells Baculovirus vectors can mediate an immune response against an antigen when it is displayed on the viral surface or when it is expressed from the baculovirus backbone using promoters which are active in mammalian cells Their ability to accommodate very large inserts of foreign DNA the lack of a preexisting neutralizing immunity to baculoviruses in humans and the easy generation of high titer virus stocks are further clear advantages of this vector system for the delivery of a vaccine In order to use baculoviruses for an induction of a specific immune response we inserted a P falciparum circumsporozoite CS protein expression cassette driven by the strong CMV promoter into the baculoviral genome AcNPV CSFVI An expression of the CS protein in antigen presenting cells APC should activate CD8 T cells via MHC I presentation The display of a second recombinant CS peptide in the viral envelope was achieved by fusion of the CS gene to the main baculovirus surface protein gp64 AcNPV CS gp64 This envelope modified baculovirus mimics the parasite to induce CD4 T cells and CS specific antibodies following uptake into APC and antigen presentation by MHC II A third vector AcNPV CSFVI CS gp64 was constructed to combine expression and presentation of CS antigens in mammalian cells