OBJECTIVETo establish strategies for preventing graft versus host disease (GVHD) and reducing treatment associated morbidity while preserving graft versus leukemia (GVL) effect in nonmyeloablative allogeneic bone marrow transplantation (allo-BMT), with or without donor lymphocyte infusion (DLI) after BMT.

METHODS3 x 10(7) bone marrow cells mixed with 1 x 10(7) spleen cells from the same BALB/c mouse were transplanted into the nonablative irradiated inbred 615 mouse which received a single subcutaneous injection of 1 x 10(6) L615 leukemia cells three days before. The experiments were designed as follows (ten mice in each group): myeloablative BMT control group (group A), nonmyeloablative conditioning without BMT group (group B), nonmyeloablative BMT group (group C), and nonmyeloablative BMT + DLI group (group D). GVL effects were assessed by survival time, white blood cell count and L615 cells in peripheral blood and histologic changes. GVHD was assessed by signs of weight loss, ruffled fur, diarrhea and histologic changes of skin, liver and small intestines. Chimerism was detected by cytogenetic analysis and PCR technique.

RESULTSThe survival time of group A, B, C and D was (20.3 +/- 13.4), (15.9 +/- 1.1), (21.6 +/- 1.7) and (37.8 +/- 2.0) days, respectively, being no significant difference between group A and group C (P > 0.05). The survival time of group C was longer than that of group B (P < 0.01). And among group B, C and D, group D had the longest survival time (P < 0.01). GVHD signs and histologic changes were observed in 60% of control group mice at + 14 day, but none of group C and group D. 40% of mice in group A died of treatment associated morbidity within two weeks, but none in group C and group D. Allogeneic chimerism was kept in group A, but excluded gradually in group C.

CONCLUSIONGVL effect seems preserved in nonmyeloablative BMT mice, but weaker than that in myeloablative BMT mice. GVL effect seems to be enhanced by DLI after nonmyeloablative BMT. GVHD and transplantation associated morbidity seems to be reduced in nonmyeloablative BMT.

Animals ; Bone Marrow Transplantation ; immunology ; methods ; Combined Modality Therapy ; Female ; Graft vs Host Disease ; prevention & control ; Graft vs Leukemia Effect ; Leukemia, Experimental ; therapy ; Leukemia, Lymphoid ; therapy ; Lymphocyte Transfusion ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Inbred Strains ; Transplantation Conditioning ; methods ; Transplantation, Heterologous

OBJECTIVETo construct a recombinant lentiviral vector (pXZ208-BDDhFVIII) mediating B-domain-deleted human coagulation factor VIII (BDDhFVIII) gene and investigate its expression in HLF, Chang-Liver and MSC cells.

METHODSBDDhFVIII gene fragment was separated by endonuclease digestion and was cloned into the multiple cloning sites of pXZ208 to construct a recombinant lentiviral vector pXZ208-BDDhFVIII. Viral particles were prepared by means of three-plasmid cotransfection of 293T package cells by calcium phosphate precipitation. After infection, the coagulant activity of human FVIII in the culture medium of 293T, HLF, Chang-Liver and MSC cells was assayed by one-stage method. The gene transduction efficiency was assayed by flow cytometry (FCM). Furthermore, PCR was performed to test the integration of BDDhFVIII.

RESULTSThe infection rates of HLF, Chang-Liver and MSC were (74.52 +/- 7.57)%, (27.24 +/- 6.53)% and (42.34 +/- 5.84)% respectively. The activities of FVIII in supernatants of HLF, Chang-Liver and MSC were (54.1 +/- 5.6)%, (22.5 +/- 2.9)% and (12.5 +/- 2.7)% respectively. BDDhFVIII gene integration was detected in all the infected cells.

CONCLUSIONThe recombinant lentiviral vector pXZ208-BDDhFVIII was successfully constructed and efficiently integrated into target cells to express human FVIII activity in vitro.

Cell Line ; Factor VIII ; biosynthesis ; genetics ; metabolism ; Gene Expression ; Genetic Vectors ; Humans ; Lentivirus ; genetics ; Plasmids ; Transfection

BACKGROUNDThe B7/CD28 pathway provides critical costimulatory signals for complete T cell activation, and members of this pathway have served as useful targets for immunotherapeutic strategies. In this study, we investigated the RNA interference (RNAi) effect induced by small interfering RNA (siRNA) targeting CD28 mRNA on human lymphocytes and its specificity.

METHODSAccording to CD28 gene sequence, we designed and synthysized three different siRNAs (siRNA-1, siRNA-2, siRNA-3) containing 21 bases using Silencertrade mark siRNA construction kit. These siRNAs were transfected into freshly isolated human lymphocytes with Lipofectamine 2000 reagent. At 24-hour, 48-hour and 72-hour post transfection, these cells were collected and analyzed. The changes of surface expression of CD28 gene were detected by flow cytometry, and the changes of CD28 mRNA levels were determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The cell viability of transfected lymphocytes was determined by methyl thiazolyl tetrazolium (MTT) assay and trypan blue dye exclusion assay.

RESULTSThree siRNAs (siRNA-1, siRNA-2, siRNA-3) specifically targeting CD28 mRNA were successfully designed and constructed. Flow cytometry analysis showed that a decrease in CD28 expression was detectable at 24-hour post transfection. Different siRNA showed different inhibition effects on CD28 expression. At 48-hour post transfection, the degrees of reduction with siRNA-1, siRNA-2 and siRNA-3 were 22.10% +/- 1.63%, 73.50% +/- 1.02% and 42.90% +/- 0.89% respectively compared with the control (P < 0.001). Neither of the groups transfected only with siRNA or lipo showed marked reduction in CD28 expression (3.15% +/- 0.75% and 4.55% +/- 0.80%) (P > 0.05). Moreover, lymphocytes treated with siRNA-co showed no marked reduction in CD28 expression (5.07% +/- 0.96%) (P > 0.05). The results of semi-quantitative RT-PCR assay indicated CD28 mRNA level was inhibited after transfection of specific siRNAs. At least 4-fold of reduction in siRNA-2 group occurred at 48-hour post transfection compared with the control (P < 0.001). MTT assay and trypan blue dye exclusion assay demonstrated that the viable cell rations of transfected lymphocytes were significantly reduced in siRNA-1, siRNA-2 and siRNA-3 groups at 48-hour post transfection (P < 0.01). The control groups showed no marked reduction in cell viability (P > 0.05).

CONCLUSIONSThree different siRNAs were synthesized and transfected into lymphocytes. They could reduce the expression of CD28 and the CD28 mRNA level. siRNA-2 was the most efficient. The cell viability reduced correspondingly. Therefore, the silencing effect on CD28 mRNA induced by siRNA may contribute to costimulatory blockade. This result show that siRNA may be useful for further study on graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (allo-BMT).

Adolescent ; Adult ; CD28 Antigens ; genetics ; Cell Survival ; Cells, Cultured ; Flow Cytometry ; Gene Silencing ; Humans ; Lymphocytes ; metabolism ; RNA, Small Interfering ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo observe the effect of Wnt3a-transduced mouse bone marrow mesenchymal stem cells (MSC) on the proliferation of T lymphocytes.

METHODSMSC were isolated from C57BL/6 mouse bone marrow and expanded in vitro, then identified by flow cytometry and their differentiation capacity into osteocytes and adipocytes were determined. Recombinant plasmids containing Wnt3a gene, were transfected with lipofectamine into HEK293 cells by the AdEasy system. Viral particles were collected to infect MSC and adenovirus vector expressing GFP (Ad-GFP) was used as control. The expression of GFP in MSC was observed using fluorescence microscopy and the protein levels of Wnt3a and β-catenin were determined by Western blot. Wnt3a-transduced and Ad-GFP transduced MSC were separately cocultured with spleen lymphocytes stimulated by ConA, at the ratio of 1:100, 1:50 or 1:10 respectively. The proliferation rate of T lymphocytes was estimated by Cell Cout Kit-8 (CCK-8) and the level of cytokine by ELISA.

RESULTSFCM analysis showed that the MSC were highly positive for CD90.2, CD44 and negative for CD34, CD45, they could differentiate into osteoblasts and adipocytes after induction; The titer of recombinant adenoviruses was up to 1 × 10(10) pfu/ml. After infected with the adenoviruses, MSC had the strongest GFP expression at 72 h and the efficiency of infection was 50%-60%. The expressions of Wnt3a and β-catenin protein in the Wnt3a-transduced MSC were significantly increased. MSC could suppress the proliferation of T lymphocytes in a dose-dependent manner. When MSC cocultured with spleen lymphocytes at 1:10 ratio, T lymphocyte proliferation rate and the level of IFN-γ were (55.41 ± 1.75)% and (326.70 ± 14.41) pg/ml respectively in Ad-GFP transduced MSC group, while in Wnt3a-transduced MSC group, they were (37.27 ± 2.66)% and (218.80 ± 12.93) pg/ml respectively. There was no effect on the production of IL-2.

CONCLUSIONCompared to Ad-GFP transduced MSC, Wnt3a-transduced MSC exhibit a more potent inhibitory effect on the proliferation of T lymphocytes.

Animals ; Bone Marrow Cells ; cytology ; metabolism ; Cell Differentiation ; Cell Proliferation ; Female ; Lymphocyte Activation ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; T-Lymphocytes ; cytology ; Transduction, Genetic ; methods ; Wnt3A Protein ; genetics ; metabolism

OBJECTIVETo construct a three plasmids lentiviral vector containing canine coagulation factor IX (cFIX) gene with ubiquinone promoter (PUB) and observe the expression of cFIX gene.

METHODSLentivirus was generated by transient three-plasmid transfection, namely, the VSV-G envelope expression cassette, the delta NRF packaging plasmid and the PTK 164 plasmid. Viral particles were used to infect the target cell, third passage mesenchymal stem cells (MSCs) and 293T cell respectively at MOI 3: 1. The cFIX activity was detected in cultured cells with one-stage clotting assay.

RESULTSThe MSCs were obtained in vitro. The lentivirus infected MSCs and 293T cells all expressed the active factor IX with the activity of (26.30 +/- 2.10)% and (19.70 +/- 1.53)%, respectively, which are significantly higher than that of control (1.00 +/- 0.05)%.

CONCLUSIONSThe lentiviral vector of three plasmids with ubiquinone promoter (PUB) was constructed and can transfect the MSCs and 293T cells.

Animals ; Bone Marrow Cells ; metabolism ; Cells, Cultured ; Dogs ; Factor IX ; genetics ; metabolism ; Genetic Vectors ; Hemophilia B ; genetics ; metabolism ; Humans ; Lentivirus ; genetics ; Plasmids ; genetics ; Transfection

OBJECTIVETo explore the killing effect of the mutant herpes simplex virus thymidine kinase (HSV-sr39tk) and its wild-type (HSV-tk) mediated by lentiviral vector on T lymphocytes in vitro and compare T cell survival rate after GCV or ACV treatment.

METHODSThe three-plasmid lentiviral vector system including packaging plasmid DeltaNRF, envelope plasmid VSV-G and vector plasmid (pTK151 + HSV-sr39tk or pTK151 + HSV-tk) were cotransfected into human embryonic kidney 293T cells using modified calcium phosphate precipitation methods. The packaged virus was harvested 72 h later. The survival of T cells expressing HSV-sr39tk or HSV-tk was measured by MTT assay after 4 day-culture against a gradient of GCV or ACV concentrations.

RESULTSThe three plasmids were effectively cotransfected and a high titre of lentivirus was obtained (2 x 10(6) IU/ml). 39tk(+) T cell survival rates declined promptly when the prodrug GCV/ACV concentrations increased from 0 micromol/L to 10 micromol/L. The T cell survival rates in GCV group declined from (96.04 +/- 3.23)% to (36.76 +/- 4.38)% while in ACV group from (97.31 +/- 4.61)% to (43.75 +/- 8.99)%. However, when GCV/ACV concentrations were more than 10 micromol/L, further decline of 39tk(+) T cell survival rates became unobvious. The growth rate of 39tk(+) T cell exposed to GCV or ACV was obviously lower than that in un-transfected T cells (P < 0.05). Tk(+) T cells were sensitive to GCV (P < 0.05), but not to ACV (P > 0.05). There was a significant difference in killing effects between 39tk(+) T cell + GCV group and tk(+) T cell + GCV group (P < 0.05).

CONCLUSIONThe lentiviral vectors containing HSV-sr39tk gene could infect T lymphocytes effectively and stably without affecting the proliferation of the transduced cell. In contrast to HSV-tk gene, T cells infected HSV-sr39tk were more sensitive not only to GCV but also to ACV.

Acyclovir ; pharmacology ; Animals ; Cell Survival ; drug effects ; Cells, Cultured ; Ganciclovir ; pharmacology ; Genetic Vectors ; Lentivirus ; genetics ; Mice ; Mice, Inbred C57BL ; Plasmids ; genetics ; T-Lymphocytes ; cytology ; drug effects ; Thymidine Kinase ; genetics ; Transfection

Adrenal Hyperplasia, Congenital ; genetics ; Chromatography, High Pressure Liquid ; Deoxyribonucleases, Type II Site-Specific ; metabolism ; Female ; Humans ; Point Mutation ; genetics ; Polymerase Chain Reaction ; methods ; Pregnancy

This study was aimed to propagate and identify the prdm1 gene-knockout mice, so as to lay the foundation for studying Blimp-1 protein. Two kinds of transgenic homozygous mice with B6.prdm1(flox/flox) and B6.Lck-Cre were feed and propagated; after successful propagating, the first passage mice were obtained; after the first passage mice were copulated once again, the genotypes were obtained as follows: B6. prdm1(wild/wild). Lck-Cre, B6. prdm1(wild/wild), B6.prdm1(flox/flox). Lck-Cre, B6.prdm1(flox/wild). Lck-Cre, B6.prdm1(flox/flox), B6. prdm1(flox/wild). The genomic DNA of second passage mice was extracted, the Cre and loxp gene fragments were amplified by PCR, then the size of Cre and loxp genomic DNA were detected by agarose gel electrophoresis. The mice with B6.prdm1(flow/flox). Lek-Cre were used as conditionally prdm1-knockout mice, B6.prdm1(flox/wild). Lck-Cre mice, B6.prdm1(flox/flox) and B6 mice were used as controls. The spleen T lymphocytes and B lymphocytes were sorted by using magnetic beads, the blimp-1 target protein was identified by Western blot. The results showed that the two transgenic homozygous mice had the ability to reproduce, and the separation ratio of second passage mice generated from propagation of their offspring cach other meet Mendelian laws, and the prdm1 gene-knockout mice also could successfully obtained. It is concluded that the application of Cre-loxp system may successfully obtain plentiful prdm1 gene-knockout mice.
Animals ; Genotype ; Mice ; Mice, Inbred C57BL ; genetics ; Mice, Knockout ; genetics ; Reproduction ; Transcription Factors ; genetics

This study was aimed to investigate the protective effect of Wit3a gene modification on mouse bone marrow mesenchymal stem cells against the injury induced by Ara-C. The gene-modified MSC steadily expressing Wnt3a were established by adenovirus system. The acute direct damage effects of different concentrations of Ara-C on the unmodified MSC and the gene-modified MSC were assessed by using an in vitro culture system, and the corresponding controls were set. The proliferation and apoptosis of MSC exposed to Ara-C were detected by cell count kit-8 (CCK-8) and flow cytometry. The expression of BCL-2 protein related with cell apoptosis was assayed by Western blot. The results indicated that as compared with unmodified MSC, Ara-C exhibited a less inhibitory effect on the proliferation of gene-modified MSC. There was obvious difference between unmodified MSC and gene-modified MSC (p < 0.05). The proliferation of gene-modified MSC began to recover at 72 hours after removal of Ara-C. However, unmodified MSC showed sustained suppression of proliferation after withdrawal of Ara-C. In apoptosis, the apoptosis rate of gene-modified MSC induced by Ara-C was significantly lower than those of unmodified MSC (p < 0.05). In addition, the expression levels of BCL-2 protein in gene-modified MSC were up-regulated compared with unmodified MSC (p < 0.05). It is concluded that Wnt3a gene modification can significantly mitigate the damage of mouse bone marrow MSC induced by Ara-C.
Animals ; Bone Marrow Cells ; drug effects ; metabolism ; Cytarabine ; adverse effects ; Mesenchymal Stromal Cells ; drug effects ; metabolism ; Mice ; Organisms, Genetically Modified ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; Wnt3A Protein ; genetics

OBJECTIVETo rapidly and sensitively detect the four virulence-associated factors of Streptococcus suis, a multiplex PCR was developed.

METHODSIn the process of this reaction, four distinct DNA targets were amplified. One target was based on the serotype 2 (and 1/2) specific cps gene and the others were based on Streptococcus suis mrp, epf (epf*) and sly gene, encoding the MRP, EF(EF*) and Sly proteins of Streptococcus suis. 72 isolates, which including 48 strains of Streptococcus suis and 24 strains of negative control, and 49 clinical specimens were detected by the multiplex PCR assay.

RESULTSAll PCR products were detected by electrophoresis on 1.2% agarose gels. With the 48 Streptococcus suis strains, the positive detection rates of cps2+, mrp+, epf+, epf*+ and sly+ were 16/48, 14/48, 12/48, 3/48 and 26/48,respectively. The results were confirmed by bacteriological examination. There were no specific amplification products including 49 clinical specimens and 24 negative control strains.

CONCLUSIONThe results demonstrated that multiplex PCR was a highly specific and sensitive diagnostic tool for the detection of virulence-associated factors of streptococcus suis.

Bacterial Proteins ; genetics ; Polymerase Chain Reaction ; methods ; Streptococcus suis ; genetics ; pathogenicity ; Virulence Factors ; genetics