title: Diphtheria toxin A gene-mediated HIV-1 protection of cord blood-derived T cells in the SCID-hu mouse model.
abstract: The reconstitutive potential of CD34+-derived cord blood (CB) cells, transduced with a regulated diphtheria toxin A (DT-A) chain gene, was examined in SCID-hu mice harboring a conjoint organ composed of human thymus and liver (thy/liv). The DT-A-transduced cells, injected directly into the thy/liv organ, showed the same engraftment potential as control CB cells transduced with the non-DT-A parental vector. CB cells, distinguishable from the thy/liv cells by the HLA marker B7, were preferentially maintained in ex vivo culture. In the thy/liv organ, the engrafted CB cells represented >80% of the total cells. A majority of cells (>70%) in the thy/liv organ were also CD4+CD8+, as would be expected of maturing thymocytes. The incidence of double-positive cells was highest at 44 days (compared with 30 days and 80 days) after injection of CB cells. This suggested that a minimum time was required to achieve optimal proliferation of cells in the thy/liv organ but that, at later times, all of the early cells had matured. Thus, the population used for engraftment contained early cells but not self-renewing cells. The double-positive cells matured rapidly into single-positive cells (either CD4+ or CD8+) when placed in ex vivo culture. Marked cells (neo+) could readily be detected in the thy/liv-derived cells. The cells transduced with DT-A showed long-term protection in ex vivo culture against HIV T lymphotropic isolate NL4-3. This study shows that DT-A-transduced cells had no apparent disadvantage in engraftment of the thy/liv organ and did not have any toxic effects in vivo. Such cells were protected against HIV infection even when challenged more than 2 months after transduction and after a 44-day engraftment period in the thy/liv mice. These data support the feasibility of toxin gene therapy as a strategy for HIV infection.
authors.affiliation: Department of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: N K
authors.initials: NK
authors.lastname: Banda
authors.forename: R K
authors.initials: RK
authors.lastname: Akkina
authors.forename: K
authors.initials: K
authors.lastname: Terrell
authors.forename: E J
authors.initials: EJ
authors.lastname: Shpall
authors.forename: J
authors.initials: J
authors.lastname: Tomczak
authors.forename: J
authors.initials: J
authors.lastname: Campain
authors.forename: H
authors.initials: H
authors.lastname: Claman
authors.forename: L
authors.initials: L
authors.lastname: Cagle
authors.forename: G S
authors.initials: GS
authors.lastname: Harrison
mesh_terms: D000818:Animals; D003602:Cytotoxicity, Immunologic / Q000235:genetics*; D004167:Diphtheria Toxin / Q000235:genetics*; D005312:Fetal Blood / Q000166:cytology*; D016332:Fetal Tissue Transplantation; D018014:Gene Transfer Techniques; D015658:HIV Infections / Q000235:genetics* / Q000276:immunology* / Q000517:prevention & control; D015497:HIV-1; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D010446:Peptide Fragments / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology* / Q000637:transplantation / Q000821:virology*
chemical_list: D004167:Diphtheria Toxin; D010446:Peptide Fragments; C029795:diphtheria toxin fragment A