Document 0777
 DOCN  M94B0777
 TI    Reconstitution of viral immunity by the adoptive transfer of T-cell
       clones modified by gene insertion (Meeting abstract).
 DT    9412
 AU    Greenberg P; Watanabe K; Gilbert M; Nelson B; Riddell S; Univ. of
       Washington, Seattle, WA 98195
 SO    EACR-12: 12th Biennial Meeting of the European Association for Cancer
       Research. April 4-7, 1993, Brussels, Belgium, 1993.. Unique Identifier :
       AIDSLINE ICDB/94697579
 AB    The essential role of CD8+ Tc for protection from CMV disease is
       supported by studies in which we demonstrated that patients who
       endogenously reconstitute their CMV-specific CD8+ Tc response are
       protected from the development of CMV disease, whereas patients lacking
       this response are at high risk for disease. Our initial adoptive T-cell
       therapy protocol is described. None of the patients who received
       adoptive T-cell therapy developed subsequent evidence of CMV disease.
       Our laboratory is now evaluating methods to improve the efficacy and
       safety of adoptive T-cell transfer by the introduction of genes into
       T-cell clones. To improve safety, a retroviral vector containing an
       inducible suicide gene has been constructed (Targeted Genetics
       Corporation): herpes virus thymidine kinase (TK) gene has been fused in
       frame with the hph gene, resulting in a gene encoding a single
       bifunctional protein (HyTK) conferring hygromycin resistance and in
       vitro sensitivity to ganciclovir. Studies in mice have demonstrated that
       T-cell clones expressing this gene can be readily eliminated in vivo by
       the administration of nontoxic doses of ganciclovir. A clinical trial
       employing T cells modified with this gene, now underway in
       HIV-seropositive patients undergoing allogeneic BMT for the treatment of
       HIV-related lymphomas is described. The therapeutic efficacy of
       transferred CD8+ T-cell clones in murine models is limited by the
       inability of the clones to proliferate and survive long-term in vivo in
       the absence of either exogenous IL-2 or a concurrent CD4+ helper T-cell
       response. Therefore, we are attempting to modify CD8+ T cells to render
       them independent of exogenous growth factors and capable of
       proliferating in response to TCR ligation. Several types of gene
       constructs are being evaluated. The first is designed to provide the
       additional signals necessary to result in endogenous IL-2 production
       following T-cell activation. Based on previous studies of bifunctional
       CD8+ T cells isolated from mice, CD8+ Tc clones were transduced with a
       vector containing the gene for the IL-1 receptor. Such T cells
       proliferate in response to binding of ligands to both the TCR and IL-1R,
       but fail to proliferate in response to either signal alone. A second
       type of construct involves the generation of a hybrid gene, in which the
       IL-2 coding sequence is under control of a promoter normally activated
       by TCR ligation. Preliminary studies are being performed with a vector
       containing the IFN-gamma promoter driving an IL-2 cDNA. Finally, a third
       type of construct containing chimeric cytokine receptors potentially
       capable of providing an autocrine loop and delivering to a T cell the
       signal normally provided by the binding of IL-2 to its receptor is being
       evaluated. Our initial studies are with a vector containing the
       extracellular domain of the c-kit receptor fused in frame to the
       transmembrane and intracytoplasmic domains of the IL-2 receptor beta and
       gamma chains. Binding of c-kit results in dimerization of the beta and
       gamma chains and delivery of the IL-2 receptor growth signal to T cells.
       Constructs fusing the extracellular binding domains of GM-CSF with the
       intracellular IL-2 receptor beta and gamma chains are now being
       prepared.
 DE    Animal  Antigens, CD8/CHEMISTRY  Cell Division  Cloning, Molecular
       Cytomegalovirus Infections/IMMUNOLOGY/*THERAPY  DNA,
       Complementary/GENETICS  Ganciclovir/THERAPEUTIC USE  HIV Infections/DRUG
       THERAPY  Human  *Immunotherapy, Adoptive  Interferon Type II/GENETICS
       Interleukin-2/GENETICS  Mice  Receptors, Antigen, T-Cell/METABOLISM
       Receptors, Interleukin-1/METABOLISM  Simplexvirus/GENETICS
       T-Lymphocytes/PATHOLOGY  T-Lymphocytes, Cytotoxic/IMMUNOLOGY  Thymidine
       Kinase/GENETICS  Zidovudine/THERAPEUTIC USE  MEETING ABSTRACT

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