AIM: To construct a recombinant adenovirus expression vector containing CTLA4Ig gene.METHODS: The CTLA4Ig gene derived from the plasmid PCDNA3.0/CTLA4Ig by using polymerase chain reaction (PCR) was inserted into the backward position of cytomegalovirus (CMV) immediate early promoter of the shuttle plasmid (pAdTrack-CMV). After being identified by endonuclease, PCR and sequencing, the recombinant shuttle plasmid pAdTrack-CTLA4Ig was co-transformed into E.coli. BJ5183 cells with the adeoviral backbone plasmid pAdEasyl-1 to obtain the homologous recombination. The adenovirus was generated in 293 cells. A series methods such as PCR and fluorescence microscope was employed to identify the generated recombinant adenovirus. RESULTS: Recombinant CTLA4Ig adenoviruses were constructed and the titer of virus was generally up to 1.65?10 12 phaque forming units per liter (PFU/L). CONCLUSION: Success in constructing recombinant pAdTrack-CTLA4Ig will be the base of the further research on its expression in the mammalian cells, and be potenially used in the prevention of transplant rejection and autoimmunity diseases.

AIM: To investigate the feasibility and infection efficiency of MSCs as the target cells of gene delivery mediated by adenoviral vector carrying CTLA4Ig gene, and to study the mechanism of transgenic MSC to inhibit immune response ex vivo. METHODS: The recombinant adenovirus containing CTLA4Ig gene was constructed, by which rat MSCs with various multiplicity of infection (MOI) were conducted. The infection efficiency was analyzed with FACS and fluorescence microscope. The expression of CTLA4Ig protein in transgenic MSCs was detected by FACS and western blot. Co-culturing the transgenic MSCs with mixed lymphocytes, the inhibitory effect of transgenic MSCs on lymphocyte proliferation was also observed. RESULTS: The adenoviral vector delivered CTLA4Ig gene with high efficiency to MSCs. The expression of CTLA4Ig protein was detected in transgenic MSCs. The gene modified MSCs inhibited the proliferation of mixed lymphocytes and maximal inhibition rate was observed on day 4 of MLR. The inhibition induced by CTLA4Ig was donor-specific. CONCLUSION: MSCs is a promising target cell for gene delivery. The expressed CTLA4Ig specifically inhibits the lymphocyte proliferation ex vivo.

OBJECTIVETo prevent Graft-versus-host disease (GVHD) in rat model, we evaluated the feasibility of mesenchymal stem cells (MSCs) as a gene transfer target and studied the efficiency of recombinant adenovirus mediated gene therapy.

METHODSWe constructed the recombinant adenovirus containing CTLA4Ig gene. Rat MSCs of passages 3-5 were infected by the adenovirus, and the transfection efficiency was monitored by GFP markers. We performed flow cytometric analysis, immunohistochemical and Western blotting analysis to identify the CTLA4Ig expression. The gene transferred MSCs were tested for their ability to inhibit the allogeneic lymphocyte response in vitro and to prevent GVHD in a rat model.

RESULTSRecombinant adenovirus pAd-CTLA4Ig was correctly constructed and confirmed. After MSCs were infected by the adenovirus, the CTLA4Ig protein was detected not only in transgenic MSCs, but also in the culture medium. In a mixed lymphocytes response (MLR) test, the transgenic MSCs could significantly inhibit the allogeneic lymphocyte response compared with the control groups (P < 0.05). A model of GVHD was developed by transplanting bone marrow cells and spleen lymphocytes of F344 rats to lethally irradiated SD rats. The onset of GVHD could be ameliorated or prevented by co-administration of transgenic MSCs. All the rats in the control groups suffered severe acute GVHD. CTLA4Ig expression was observed in the liver, intestine, kidney and spleen 30 days post-transplantation.

CONCLUSIONSOur results indicate that adenoviral vectors could efficiently transfer CTLA4Ig gene into MSCs and sustain long-term stable expression in vitro and in vivo.

Abatacept ; Adenoviridae ; Animals ; Feasibility Studies ; Gene Transfer Techniques ; Genetic Vectors ; Graft vs Host Disease ; prevention & control ; Immunoconjugates ; genetics ; Mesenchymal Stromal Cells ; Rats ; Rats, Inbred F344 ; Rats, Sprague-Dawley ; Recombination, Genetic