       Document 0726
 DOCN  M9550726
 TI    Prolonged transgene expression in cotton rat lung with recombinant
       adenoviruses defective in E2a.
 DT    9505
 AU    Engelhardt JF; Litzky L; Wilson JM; Institute for Human Gene Therapy,
       University of Pennsylvania; Medical Center, Philadelphia 19104-4268.
 SO    Hum Gene Ther. 1994 Oct;5(10):1217-29. Unique Identifier : AIDSLINE
       MED/95151837
 AB    Recombinant adenoviruses have tremendous potential for gene therapy of
       cystic fibrosis (CF) lung disease. First-generation recombinant viruses,
       rendered replication defective by deleting E1, have been associated with
       high-level recombinant gene expression in airway epithelial cells when
       administered directly to the lung. Experience in mice and non-human
       primates indicates that transgene expression is transient (i.e., lasting
       less than 21 days) and associated with the development of inflammation.
       We suggest an hypothesis to explain these findings that is based on
       expression of viral proteins in genetically modified cells that leads to
       destructive cellular immune responses and repopulation of lung epithelia
       with non-transgene-containing cells. This hypothesis has been evaluated
       in the current study using the cotton rat model. Instillation of the
       first-generation lacZ virus, H5.010CBlacZ, into cotton rat airway led to
       high-level gene expression in conducting and respiratory airway that was
       transient and associated with a substantial mononuclear, CD8-dominated,
       infiltrates. Treatment of the animals with cyclosporine blunted the
       inflammatory response and prolonged recombinant gene expression in both
       conducting and respiratory airways. Expression of viral early and late
       genes was detected in a subpopulation of lacZ-expressing epithelial
       cells of conducting airway and alveoli. Instillation of virus into
       cotton rat tracheal xenografts grown in athymic nu/nu mice led to
       efficient and stable transgene expression in the absence of pathology,
       underscoring the importance of T cell-mediated immunity. A recombinant
       adenovirus was constructed that is disabled in its capacity to replicate
       by the introduction of a temperature-sensitive mutation in the E2a gene
       as well deletion of E1 sequences. Instillation of this virus into cotton
       rat airway led to high-level transgene expression that was more stable
       than that achieved with the first-generation virus and was associated
       with less early and late gene expression as well as a diminished
       infiltration of CD8+ T cells in conducting airway epithelium.
       Interestingly, the introduction of the E2a mutation had no effect on the
       persistence of transgene expression, the pattern of late viral gene
       expression, nor the CD8+ T cell response within alveolar cells. These
       data suggest that cell-specific variation in the cell biology of
       recombinant adenoviruses exists in the lung. The present studies in
       cotton rats confirm the role of cellular immunity in the biology of
       adenovirus-mediated gene therapy to the lung and suggest that
       modifications in the design of recombinant adenoviruses to minimize or
       ablate transgene expression will be useful in improving the potential of
       this technology for gene therapy of CF.
 DE    Adenovirus E2 Proteins/*GENETICS  Adenoviruses,
       Human/*GENETICS/IMMUNOLOGY  Animal  Antigens, Viral/IMMUNOLOGY  Cystic
       Fibrosis/*THERAPY  CD8-Positive T-Lymphocytes/IMMUNOLOGY  Female  Gene
       Deletion  *Gene Expression  *Gene Therapy  Genes, Viral  Hesperomyinae
       Lac Operon  Lung/*METABOLISM/PATHOLOGY  Male  Mice  Mice, Nude  Support,
       U.S. Gov't, P.H.S.  Viral Proteins/BIOSYNTHESIS  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

