Intravesical instillation in pure line LEW rats and nude mice.

In order to study bladder intravesical instillation methods in pure line LEW rats and nude mice, female LEW rats and nude mice aged 2 to 4 weeks were sacrificed. Their urethra and bladder were observed under anatomical microscopy. A trochar was prepared according to the outline and angle of the urethra. Ink was poured into female rats and nude mice bladder though urethra. Filling and staining of bladder were observed and evaluated under anatomical microscopy. Status and urethral injury of rats and mice were observed. The results showed that urethra anatomic structure of rats and nude mice was different from that of human urethra. When bladder was filled with ink and became blue, liquid was not seen to leak out. The success rate of intubation was high (100%). Living activities of animals weren't influenced by intravesical instillation. It was concluded that bladder irrigation might be a kind of valid and utilizable method in pure line rat and nude mouse empirical study. The model may be a more effective tool for study of bladder tumor.

[Studies on the induction of transplantation tolerance and immune reconstitution through combined strategies].

The induction of transplantation tolerance and the improvement of immune reconstitution after allogeneic bone marrow transplantation are the main research fields in the clinic organ transplantation and transplantation immunology. Over the past 5 years serial studies have been performed in our lab to induce robust transplantation tolerance by using combined strategies and improve the immune reconstitution of mice following allogeneic bone marrow transplantation by using gene-engineered bone marrow stromal cells. The results are encouraging. (1) The long-term survival of allografts was received by blockade of both CD28/B7 and CD40/CD40L or CD28/B7 and OX40/OX40L costimulation signals. In the case of blockade of both CD28/B7 and OX40/OX40L, the islet allograft survival was over 150 days compared to the control 14 days. (2) The CTLA4Ig-FasL fusion molecule expressed by adenoviral vector containing CTLA4Ig-FasL gene can prevent the autoimmune diabetes of mice and significantly prolong the survival time of cardiac allografts in rats, indicating that Fas-FasL-mediated apoptosis is able to enhance CTLA4Ig-induced transplantation tolerance. (3) In the time-window of peripheral tolerance induced by various methods, the systemic infusion of donor bone marrow cells and spleen cells obtained stable allogeneic mixed chimerism and robust transplantation tolerance. In the case of CTLA4Ig-FasL treatment combined with donor bone marrow cells more than 20% donor-origin blood cells chimerism, and more than 200 days prolonged skin allograft survival were obtained or received. (4) The murine bone marrow stromal cell line QXMSC1 transfected with IL-6 gene or IL-2+IL-3 genes significantly improved the immune reconstitution of mice following allogeneic bone marrow transplantation. Furthermore, It was observed that the mesenchymal stem cells transfected with IL-7 gene suppressed 90% of GVHD and expressed antileukemic effect, while accelerating immune reconstitution in mice following allogeneic bone marrow transplantation, which might be valuable in the clinic setting.

[Characterization of a novel transplantable orthotopic nude mouse model with xenografted human bladder transitional cell tumor (BIU-87)].

OBJECTIVE: A mouse model of orthotopic bladder cancer simulating its human counterpart is of great importance in preclinical evaluation of new treatment modalities such as immunotxin therapy. The aim of the present study is to establish a novel nude mouse model with xenografted human bladder cancer. METHODS: Single cell suspension of an established human bladder transitional cell carcinoma (TCC) cell line BIU-87 was instilled into nude mouse bladders which were pretreated with mild acid washing. The tumor growth in mouse bladder was assessed weekly by magnetic resonance imaging (MRI). At intervals following implantation and MRI tumor detection, the animals were sacrificed for necropsy, histological examination and immunocytochemical studies. RESULTS: The overall tumor establishment was 92.9% (52/56 mice) at 7 - 36 days, while in the subgroup of animals sacrificed at 12 - 13 days, 40 out of 42 animals (95.2%) developed TCC, the majority of which was superficial. The tumor stages were assessed by gross and histopathology. Histological examination confirmed the presence of grade II - III TCC. Immunocytochemistry confirmed that the tumor model maintained the biological and immunological features of BIU-87 cells. The changes seen on MRI images well correlated with the extent of tumor invasion identified by histology. Carcinoma in situ could be detected histologically at 7 - 9 days post-inoculation and progressed into papillary or invasive tumors thereafter. CONCLUSION: The orthotopic BIU-87 TCC model in nude mice is highly reproducible and is ideal for preclinical studies on experimental intravesical therapies.

[Induction of skin allograft tolerance in mice by using anti-alphabeta T cell receptor and anti-CD80 monoclonal antibodies combined with bone marrow transfusion].

OBJECTIVE: To explore the role of anti-alphabeta T cell receptor (TCR) and anti-CD80 monoclonal antibodies (mAbs) combined with donor bone marrow cells (BMCs) infusion in the induction of murine skin allografts tolerance. METHODS: On day 0, 2 x 10(8) BMCs of BALB/c mice were injected into recipient C57BL/6 mice via the tail vein, meanwhile, an intraperitoneal injection of TCRalphabeta mAb (500 microg) was given. On day 2, CD80 mAb was administered intraperitoneally. Skin grafting was performed on day 6. Delayed type hypersensitivity (DTH), mixed lymphocyte reaction (MLR), IL-2 reverse assay of MLR, adoptive transfer assay and chimerism detection were performed at different time points and tolerance mechanisms were investigated. RESULTS: The mean survival time (MST) of BALB/c skin allografts in C57BL/6 recipients that were treated by anti-TCRalphabeta and anti-CD80 mAbs combined with donor BMCs infusion was 70 days. DTH and MLR assay indicated that the tolerant mice displayed significant hyporesponsiveness. The result of IL-2 reverse test showed that clone anergy was probably involved in the formation of tolerance in the tolerant C57BL/6 mice. In vivo and in vitro adoptive transfer assay, suppressive activity in the spleens of tolerant C57BL/6 mice was observed. Chimerism existed in both the thymus and spleen of the tolerant C57BL/6 mice. The chimerism level gradually declined with time. CONCLUSION: Treatment of anti-TCRalphabeta and anti-CD80 mAbs combined with donor BMCs infusion can successfully induce a long-term tolerance in BALB/c mice to C57BL/6 skin graft. Multiple mechanisms, including clone anergy, suppressor cells and chimerism are involved in the tolerance.

Cytokines transduced bone marrow stromal cell lines promote immunohematopoietic reconstitution in mice after allogeneic bone marrow transplantation.

Impaired immune reconstitution following allogeneic T-cell depleted bone marrow transplantation (allo-TCD-BMT) is a major obstacle to its clinical application. Stromal cell line QXMSC1, established from bone marrow cells of BALB/c(H-2d), was transfected with murine IL-3 and/ or IL-2 gene, and injected into lethally irradiated C57BL/6(H2b) mice. We evaluated its effects on immunologic and hematopoietic reconstitution after allo-TCD-BMT. The results showed that QXMSC1-IL-3 + IL-2 could significantly increase the numbers of hematopoietic primitive progenitors (CFU-S), committed progenitors (CFU-GM, and BFU-E), and lymphocytes (CD8+ cells, CD4+ cells, and B cells). Similarly, immune functions of recipient mice were significantly enhanced in the QXMSC1-IL-3 + IL-2 group. In addition, QXMSC1-IL-3 or QXMSC1-IL-2 also exerted apparent effects on accelerating immune reconstitution, but these effects were far less than that of QXMSC1-IL-3 + IL-2. Our results demonstrated that stromal cell-mediated IL-3 and IL-2 gene therapy may be a potent approach in promoting immunologic and hematopoietic reconstitution after allo-TCD-BMT.

Preparation of arsenic trioxide-loaded albuminutes immuno-nanospheres and its specific killing effect on bladder cancer cell in vitro.

BACKGROUND: Recently, arsenic trioxide (As2O3) was considered as a novel anti-tumor agent. However, it showed severe toxicity effect on normal tissue at the same time. To improve its therapeutic efficacy and decrease its toxicity,we prepared arsenic trioxide-loaded albuminutes immuno-nanospheres [As2O3-(HAS-NS)-BDI-1] targeted with monoclonal antibody (McAb) BDI-1 and tested its specific killing effect against bladder cancer cell. METHODS: As2O3-HAS-NS was prepared by chemical cross-linking method. Monoclonal antibody BDI-1 was purified with ammonium sulphate saltingout and chromatography. Albuminutes microspheres were conjugated with McAb by SPDP cross-linking method. Concentration of As in As2O3-(HAS-NS)-BDI-1 and As2O3-HAS-NS was measured by atomic fluometry method. As2O3-(HAS-NS)-BDI-1 and its activity were detected by SDS-PAGE reduction electrophoresis, indirect immunofluorescence test, light microscope and scanning electron microscope observation. Acridine orange staining and tritiated thymidine (3H-TdR) incorporation tests were used to indicate specific killing activity of As2O3-(HAS-NS)-BDI-1 in vitro. RESULTS: In As2O3-(HAS-NS)-BDI-1 groups, we saw two protein bands in SDS-PAGE reduction electrophoresis. Albuminutes immuno-nanospheres were rounded with clear green fluorescence by immunofluorescence test. Under microscope, we observed that BIU-87 cells were covered with the As2O3-(HAS-NS)-BDI-1 and that As2O3-(HAS-NS)-BDI-1 moved with the BIU-87 cells. The albuminutes immuno-nanospheres were tightly junctioned with the BIU-87 cells. Specific killing activity of As2O3-(HAS-NS)-BDI-1 on bladder tumor cells was observed by acridine orange staining and 3H-TdR incorporation assays. CONCLUSIONS: As2O3-(HAS-NS)-BDI-1 might bind specifically against BIU-87 cells, thus leading to high activity of killing bladder tumor cells.

Induction of xenogeneic islet transplantation tolerance by simultaneously blocking CD28-B7 and OX40-OX40L co-stimulatory pathways.

It has been demonstrated that prolonged graft survival can be achieved through inhibiting the activation of T cells, and addition of soluble CTLA4Ig and OX40Ig proteins to mixed lymphocyte reactions can effectively inhibit T cell proliferation. To explore the potential of this type of treatment in xenotransplantation, we infected streptozotocin-induced diabetic BalB/c mice (H-2d) (200 mg/kg, IV) with 5 x 10(8) pfu AdCTLA4Ig-IRES-OX40Ig on day 1 before islets transplantation through the tail vein. The results showed that this treatment prolonged the islet xenografts survival significantly. The reaction to exogenous glucose stimulation was normal and the cytokine secretion of the type Th1 cells was inhibited. The AdCTLA4Ig-IRES-OX40Ig-mediated treatment effectively induced the T cells into anergy and the Th1/Th2 cells into deviation. These results strongly supported the therapeutic potential of blockade of costimulation by AdCTLA4Ig-IRES-OX40Ig genes transfer in inducing the organ transplantation tolerance.

Preparation of arsenic trioxide albumin microspheres and its release characteristics in vitro.

Arsenic trioxide albumin microspheres (As2O3-BSA-NS) were prepared by using methods of chemical cross-linking. The desirability function (DF), calculated according to the size (<1 microm) distribution, drug loading and drug trapping efficiency, was introduced as a total index for the microspheres formulation. Four factors, inculding W/O ratio, decentralization speed, BSA concentration and stirring stabilization time, were selected and arranged in an orthogonal experimental table. The release characteristic was studied by the drug release experiment in vitro. The four factors affected DF differently. Decentralization speed behaved as the maximum (P<0.01), followed by BSA concentration (P<0.05) and the W/O ratio dose (P<0.05). Stirring stabilization time did not influence DF (P>0.05). The release experiment in vitro showed that As2O3 in As2O3-BSA-NS was released more slower than pure As2O3. It was concluded that regular As2O3-BSA-NS may be prepared by the methods of chemical cross-linking, which was optimized by orthogonal experimental analysis of different factors, and the microspheres can release As2O3 slowly.

[Adenovirus-mediated CTLA4Ig and OX40Ig gene transfer induces long-term survival of cardiac allografts in rats].

OBJECTIVE: To investigate the potential role of CTLA4Ig gene and OX40Ig protein in inducing transplantation tolerance and the mechanisms thereof. METHODS: Thirty Lewis rats underwent transplantation of the hearts of DA rats and then randomly divided into five equal groups: control group, blank virus AdEGFP treated group (adenovirus containing EGFP at the dose of 1-5 x 10(9) pfu/ml was infused via portal vein immediately after the operation), AdCTLA4Ig treated group, AdOX40Ig treated group, and AdCTLA4Ig-IRES-OX40Ig treated group. The cardiac allograft survival was monitored by daily palpation. The total cessation of beating was defined as rejection and was confirmed by histology. Peripheral venous blood samples were collected 0, 3, 7, 10, 14, 21 and 28 days after the administration of adenovirus. ELISA was used to detect the expression of CTLA4Ig and OX40Ig. Twenty days after the heart transplantation single splenocyte suspension was prepared from surviving Lewis rats to be used as responder. The spleens of the normal donor-DA rats and the third strain DA rats to prepare single cell suspension of the same density to perform mixed lymphocyte reaction (MLR). Then recombinant IL-2 was added into the mixed MLR system to observe t\if the MLR could be reversed. Twenty days after the heart transplantation the splenocytes of the tolerating Lewis rats were injected into the lingual vein of the normal Lewis rats to observe the delayed type hypersensitivity (DTH) of the transferred Lewis rat to normal rat splenocytes. RT-PCR was used to detect the mRNA expression of IL-2, interferon-gamma, IL-4, and IL-10. RESULTS: The survival time of the AdCTLA4Ig-IRES-OX40Ig treated group was 151.5 d +/- 42.6 d, significantly longer than those of the AdOX40Ig treated group (60.2 d +/- 11.4 d (P = 0.003), AdCTLA4Ig (43.2 d +/- 11.1 d, P = 0.0026), control group (5.7 d +/- 0.5 d, P = 0.000 43), and AdEGFP treated group (5.2 d +/- 0.4 d, P = 0.000 43). CTLA4Ig and/or OX40Ig proteins were expressed at a high level in the adenoviral treated rats. Compared with the control group the splenocytes of the AdCTLA4Ig-IRES-OX40Ig, AdCTLA4Ig, and AdOX40Ig treated groups displayed donor-specific hyporesponsiveness (P = 0.0016, 0.0026 and 0.001), which could be partly reversed by the addition of exogenous IL-2. Moreover, the hyporesponsiveness could be transferred to the same strain rats through adoptive transfer. In comparison with the normal controls, the expression of Th1 type cytokines, such as IL-2 and IFN-gamma, was significantly decreased in the tolerating rats and significantly increased in the rats with rejection; however the expression of the Th2 type cytokines, such as IL03 and IL-10, was significantly increased in the tolerating rats and significantly decreased in the rats with rejection, showing a deviation of Th1/Th2 type cytokines. CONCLUSION: AdCTLA4Ig-IRES-OX40Ig-mediated genes transfer renders prolonged expression of CTLA4Ig and OX40Ig in Lewis recipient rats, leading to a long-term survival of cardiac allografts. The induced tolerance is donor-specific, and the mechanisms may be associated with T cell anergy, deviation of Th1/Th2, and the regulatory T cells.

Bone marrow stromal cell line co-transfected with IL-2 and IL-3 genes can accelerate restoration of T-cell immunity in allo-BMT mice.

BACKGROUND: After T-cell depleted allogeneic bone marrow transplantation, impaired immune reconstitution is a major cause of morbidity and mortality in the recipient. The purpose of this study was to observe the effects of the gene-engineered bone marrow stromal cell line QXMSC1-IL-2 + IL-3 on the reconstitution of T-cell immunity in allo-BMT mice. METHODS: The bone marrow stromal cell line QXMSC1 was co-transfected with IL-2 and IL-3 genes using a Tet-on gene expression system. T lymphocyte subset counts per spleen were analyzed by flow cytometry. Lymphocyte proliferation response to ConA was examined to evaluate T-cell function. CDR3 spectratyping techniques were performed to evaluate TCR repertoire diversity at various time points post-transplantation. RESULTS: Gene engineered bone marrow stromal cell line QXMSC1-IL-2 + IL-3 could express IL-2 and IL-3 [1,300 ng.day(-1).10(-6) cells and 1100 ng.day(-1).10(-6) cells, respectively] under the control of doxycycline. QXMSC1-IL-2 + IL-3 in combination with allogeneic bone marrow could significantly increase the counts of CD(4)(+) and CD(8)(+) T cell, 1.72 and 1.27-fold respectively at week 3 compared with TCD-BMT group (P < 0.01); make CD(4)(+)/CD(8)(+) ratio return to normal level at week 4; enhance splenocytes mitotic response to ConA (P < 0.01), and accelerate restoration of TCR repertoire diversity in the lethally irradiated mice (P < 0.05). CONCLUSION: The gene transduced stromal cell line QXMSC1-IL-2 + IL-3 is able to accelerate T-cell immunity in allo-BMT mice.

[Adenovirus-mediated CTLA4-FasL gene transfer induces long-term survival of cardiac allograft in rats].

OBJECTIVE: To investigate the potential of exogenously expressed CTLA4-FasL in inducing transplantation tolerance using rat cardiac graft model and its related mechanisms. METHODS: The heart allograft of DA rat was placed in the abdomen of LEW rat, and adenoviruses containing CTLA4-FasL gene (AdCTLA4-FasL) adenovirus containing CTLA4Ig, and AdEGPP were infused at a dose of 5 x 10(9) pfu/ml via portal vein in different recipients respectively immediately after the operation. DA-->LEW cardiac graft controls and syngeneic LEW-LEW cardiac graft controls were used. The survival of cardiac allografts was monitored by daily palpation. The total cessation of beating was defined as rejection and was confirmed by histology. The serum level of CTLA4-FasL was measured via ELISA. The tolerance mechanisms were investigated with adoptive transfer, mixed lymphocyte reaction (MLR), IL-2 reverse experiment, determinations of frequencies of HTLp and CTLp, and analysis of the polarization of TH1/TH2 type cytokines using RT-PCR. RESULTS: The survival of DA allografts were prolonged significantly in LEW recipients receiving AdCTLA4-FasL with a mean survival time of 71.0 +/- 23.7 d (n = 6), significantly longer than those of the untreated recipients (5.7 +/- 0.5 d, n = 6), AdEGFP-treated recipients (5.2 +/- 0.4 d, n = 6) and AdCTLA4Ig-treated recipients (45.7 +/- 12.4 d, n = 6) (call P < 0.05). Prolonged expression of serum CTLA4-FasL was shown in AdCTLA4-FasL-treated rats. Splenocytes of LEW recipients with long-term surviving cardiac allograft displayed donor-specific hyporesponsiveness, which could not be reversed in the presence of exogenous added IL-2 in MLR. Frequencies of HTLp and CTLp were significantly reduced. The polarization of TH1/TH2 type cytokines was not shown. CONCLUSION: Adenovirus-mediated CTLA4-FasL gene transfer renders prolonged therapeutic expression of CTLA4-FasL in LEW recipient rats, leading to long-term survival of cardiac allografts. The induced tolerance is donor-specific, and may result from regulatory T cells and the deletion of alloreactive T cells. However, T cell anergy and the deviation of TH1/TH2 type cytokines may not be the involved mechanism, at least when tested.

[Effect of T suppressor cells on the maintenance phase of tolerance to cardiac allografts in the rats].

OBJECTIVE: To study the role of T suppressor cells in immune tolerance to cardiac allografts in the rats. METHODS: Male DA rat hearts were transplanted to male Lewis rats using Ono's model and randomly divided into five groups: group 1: untreated, group 2: portal venous injection of 3 x 10(8) DA splenocytes to Lewis rat, group 3: intraperitoneal injection of cyclophosphamide (80 mg/kg) to Lewis rat, group 4: portal venous injection of 3 x 10(8) DA splenocytes combined with intraperitoneal injection of cyclophosphamide (80 mg/kg) to Lewis rat, 15 days later heart transplantation was performed. Group 5: intravenous injection 3 (108 splenocytes of group 4 to normal recipient, and then heart transplantation was performed. Mean survival time (MST), histological changes, mixed lymphocyte reaction (MLR) were measured after operation. RESULTS: The survival time of heart allografts in the group 4 [MST: (71.5 +/- 29.1) d, t = -14.063, -13.915, -13.777; P < 0.01] was significantly longer than in the groups of 1 [MST: (7.3 +/- 1.0) d], 2 [MST: (7.8 +/- 0.8) d], 3 [MST: (8.2 +/- 1.1) d ]. Only a few inflammatory cells infiltrated in cardiac allografts in the groups of 4 and 5. MLR in the groups of 4 and 5 were significantly decreased compared with those of normal control (t = 29.902, 23.047; P < 0.01). CONCLUSIONS: Portal venous injection of donor splenocytes combined with intraperitoneal injection of cyclophosphamide could induce immune tolerance to cardiac allografts. The immune tolerance could be transferred through splenocytes. T suppressor cells play an important role in the immune tolerance.

[Induced tolerance to cardiac allografts with multiple intravenous injection of donor spleen cells].

OBJECTIVE: To study the methods and mechanisms of immune tolerance in cardiac transplantation. METHODS: Male DA rat hearts were transplanted to male Lewis rats using Ono's model and randomly divided into five groups: untreated, intravenous injection of 1 x 10(8) DA splenocytes to Lewis rat, intraperitoneal injection of cyclophosphamide (100 mg/kg) to Lewis rat, intravenous injection of 1 x 10(8) DA splenocytes combined with intraperitoneal injection of cyclophosphamide (100 mg/kg) to Lewis rat, multiple injection of DA rat splenocytes with intraperitoneal injection of cyclophosphamide, 11 days later heart transplantation was performed. Mean survival time (MST), histological changes, mixed lymphocyte reaction (MLR), the role of interleukin-2 (IL-2) to MLR and the role of tolerant rat splenocytes to MLR were measured after operation. RESULTS: The survival time of heart allografts in the group of multiple injection of DA rat splenocytes with intraperitoneal injection of cyclophosphamide [MST: (85.3 +/- 7.5) d, t = 0, P < 0.01] was significantly longer than in the groups of untreated [MST: (7.3 +/- 1.0) d], intravenous injection of 1 x 10(8) DA splenocytes to Lewis rat [MST: (7.9 +/- 0.9) d], intraperitoneal injection of cyclophosphamide (100 mg/kg) to Lewis rat [MST: (8.1 +/- 1.2) d], intravenous injection of 1 x 10(8) DA splenocytes combined with intraperitoneal injection of cyclophosphamide (100 mg/kg) to Lewis rat [MST: (25.8 +/- 3.5) d]. Only a few inflammatory cells infiltrated in cardiac allografts in the group of multiple injection of DA rat splenocytes with intraperitoneal injection of cyclophosphamide. MLR in the group of multiple injection of DA rat splenocytes with intraperitoneal injection of cyclophosphamide were significantly decreased compared with those of normal control (t = 0, P < 0.01). IL-2 could partly reversed the hyporesponsiveness of MLR in tolerant rats, the tolerance could be transferred in vitro. CONCLUSIONS: Multiple injection of donor splenocytes combined with intraperitoneal injection of cyclophosphamide to recipients could induce immune tolerance to cardiac allografts.

Intranasal inoculation of Chlamydia trachomatis mouse pneumonitis agent induces significant neutrophil infiltration which is not efficient in controlling the infection in mice.

Previous studies have shown that chlamydial infection is accompanied by significant infiltration of neutrophils at the site of infection. However, the role of neutrophils in host defence against chlamydial infection is not clearly understood. Using genetically different inbred mouse strains and CXCR-2 gene knockout (KO) mice, we examined the mechanism for neutrophil recruitment and the role of neutrophils during chlamydial lung infection. Our data showed that C3H mice exhibited significantly higher and more persistent neutrophil infiltration in the lung than did C57BL/6 mice following Chlamydia trachomatis mouse pneumonitis infection. The massive neutrophil infiltration in C3H mice was paralleled by high-level expression of CXCR-2 and its ligands, CXC chemokines (macrophage inflammatory protein 2, cytokine-induced neutrophil attractant (KC) and lipopolysaccharide-induced CXC chemokine), and proinflammatory cytokines (tumour necrosis factor-alpha, interleukin-1 and interleukin-6) in the lung. Although much greater infiltration of neutrophils was observed in C3H mice than in C57BL/6 mice, the former mice had more severe disease and higher in vivo chlamydial growth than the latter. Moreover, CXCR-2 KO mice, which revealed a dramatic reduction in neutrophil activity, showed comparable chlamydial infection to wild-type mice. These results suggest that neutrophils are not efficient for controlling chlamydial lung infection.

[The enhancing effects of IL-3 gene transfected murine bone marrow stromal cells on hematopoiesis under control of doxycycline].

To study enhancing effect of IL-3 gene transfected bone marrow stromal cell which can be induced by doxycycline (Dox) to express IL-3 cytokine on the proliferation and differentiation of hematopoietic stem cell, retrovirus vector system contained mIL-3 cDNA was established and bone marrow stromal cell line was transfected, and obtained QXMSC1Tet-on-IL-3, in which expression level of IL-3 can be modulated by Dox. The activities of IL-3 were measured under different Dox concentrations. The numbers of hematopoietic progenitors (CFU-GM, CFU-E, CFU-GEMM and LTC-IC) were measured and the capacity of QXMSC1Tet-on-IL-3 sustaining hematopoietic progenitor cell growth was evaluated. The results showed that IL-3 gene transfected stromal cell line QXMSC1-Tet-on + IL-3 expressed high concentration of IL-3 in vitro under control of Dox. The supernatant of QXMSC1-Tet-on + IL-3 was able to increase the number of CFU-GM, CFU-E and CFU-GEMM. The total numbers of nucleated cells and long-term cultured colonies increased in LTC-IC assay. It is concluded that in the culture of QXMSC1-Tet-on + IL-3 cells, Dox actually enhanced IL-3 expression, and thus augmented the proliferation and differentiation of hematopoietic stem/progenitor cells in vitro.

[Promotion of post BMT hematopoiesis reconstitution by cotransplantation of IL-3 transfected marrow stromal cells in mice].

OBJECTIVE: To explore whether bone marrow stromal cell line QXMSC1 (H-2(d)) engineered to secrete IL-3 (QXMSC1 IL-3) can improve the hematopoiesis post-allogeneic bone marrow transplantation (BMT) in mice. METHODS: The stromal cell line QXMSC1 IL-3 was established by transfecting QXMSC1 (H-2(d)) cell with a recombined retrovirus vector PL3SN containing mice IL-3 gene cDNA. Lethally irradiated mice C57BL/6 (H-2(b)) were transplanted with T cell depleted allogeneic bone marrow (BALB/c, H-2(d), 1 x 10(7)/mice) and QXMSC1 IL-3 cells (5 x 10(5)/mice). The numbers of RBC and WBC in peripheral blood were counted 20 and 40 days after bone marrow transplantation. The marrow nucleated cells, CFU-S, CFU-GM, CFU-E and CFU-GEMM yields were measured in recipient mice. RESULT: QXMSC1 IL-3 cells could stably secrete IL-3 and increase the peripheral RBC and WBC counts as well as the number of marrow nucleated cells and CFU-GM, CFU-E, CFU-GEMM yields. CONCLUSION: Cotransplantation of QXMSC1 IL-3 cells with T cell depleted marrow grafts improve hematopoiesis post allogeneic BMT in mice.

[Construction and biological activities of CTLA4Ig adenovirus vectors].

AIM: To construct CTLA4Ig adenovirus vectors (AdCTLA4Ig) by homologous recombination and study their activity, and to employ the vectors to induce cardiac transplantation tolerance by gene therapy. METHODS: CTLA4Ig gene was cloned to pCA13 adenovirus shuttle plasmid by recombination strategy. Construction of CTLA4Ig adenovirus vectors was performed by homologous recombination of pCA13 plasmid containing CTLA4Ig gene with adenovirus helper plasmid, followed by packaged with 293 cells. Expression and secretion of CTLA4Ig was confirmed by RT-PCR, SDS-PAGE and Western blot. The inhibitory effect of supernate of 293 cells infected with AdCTLA4Ig on MLR in-vitro was observed. A biological activity of CTLA4Ig adenovirus vectors was determined by AdCTLA4Ig gene therapy in rats in-vivo. RESULTS: The Construction of CTLA4Ig adenovirus vector was successful. It was confirmed that the supernatant of 293 cells infected with AdCTLA4Ig could inhibit MLR in-vitro. It was also showed that CTLA4Ig adenovirus vectors could induce transplantation tolerance and prolong allograft survival when they were administrated in rats in-vivo. CONCLUSION: CTLA4Ig adenovirus vectors successfully constructed can infect 293 package cells and secrete CTLA4Ig. The CTLA4Ig protein can inhibit T cell activation. The CTLA4Ig adenovirus vectors can be employed to gene therapy in-vivo, and induce transplantation tolerance.

Simultaneous administration of a low-dose mixture of donor bone marrow cells and splenocytes plus adenovirus containing the CTLA4Ig gene result in stable mixed chimerism and long-term survival of cardiac allograft in rats.

T-cell costimulatory blockade combined with donor bone marrow transfusion may induce mixed chimerism, rendering robust tolerance in transplanted organs and cells. However, most protocols entail high doses of donor bone marrow cells (BMCs) or repeated administration of costly agents that block costimulatory pathways, thus delaying clinical development. To circumvent these shortcomings, we developed a strategy in which the dosage of donor BMCs was reduced but compensated by donor splenocytes (SPLCs). Furthermore, repeated administration of costly agents was replaced with a single injection of adenovirus expressing a gene of interest. In rat cardiac transplantation models, cardiac allografts from DA (RT-1a) rats were transplanted heterotopically into the abdomen of LEW (RT-11) recipient rats. Immediately after cardiac transplantation, an adenovirus vector (AdCTLA4Ig; 5 x 10(9) plaque-forming units) containing the gene for CTLA4Ig was administered to recipients (n = 6) simultaneously with a low dose of donor BMCs (1 x 10(8)/rat) and SPLCs (5 x 10(7)/rat) via the portal vein. The treated LEW recipient rats developed long-lasting mixed chimerism (>10% at >100 days) and exhibited long-term cardiac allografts (mean survival time of > 200 days) compared with control recipients. Moreover, recipients displaying long-lasting mixed chimerism accepted subsequent donor skin allografts while promptly rejecting third-party skin allografts. These results suggest that blockade of the CD28-B7 pathway, using adenovirus-mediated CTLA4Ig gene transfer, in concert with a low dosage of donor BMCs and SPLCs, may represent a feasible strategy to induce stable mixed chimerism and permit long-term survival of cardiac allografts.

[Accelerating hematopoietic recovery in allogeneic bone marrow transplantation mice by co-infusion of marrow stromal cells transduced with dual genes of IL-3/IL-6].

To observe whether bone marrow stromal cell line QXMSC1 (H-2(d)) engineered to secrete IL-3 and IL-6 can improved the hematopoiesis in allogeneic bone marrow transplantation (allo-BMT) mice, the stromal cell line QXMSC1IL-3/IL-6 was established by QXMSC1 cells transduced with the recombined retrovirus vector pL3SN containing mouse IL-3 cDNA and pL6SN containing human IL-6 cDNA. The lethally irradiated C57BL/6 (H-2(b)) mice were engrafted with bone marrow cells (1 x 10(7) cells/mouse BALB/c mice, H-2(d)) in which T cells were depleted by anti-Thy1.2 monoclonal antibody adding complement, and QXMSC1IL-3/IL-6 cells (5 x 10(5)/mouse) were co-infused at same time. The hematopoiesis of recipient mice was observed in 20 and 40 days post-transplantation. Blood RBC and WBC were counted, and nucleated cells, CFU-S, CFU-GM, CFU-E and CFU-GEMM were assayed in recipient bone marrow. Results showed that IL-3 and IL-6 were stably expressed in QXMSCQIL-3/IL-6 cells. Compared with BMT and co-infusion with QXMSC1 or QXMSC1 pLXSN cell groups, co-graft with QXMSC1IL-3/IL-6 cells increased the number of blood RBC and WBC in the recipients, and also significantly increased nucleated cells, CFU-S, CFU-GM, CFU-E and CFU-GEMM in recipient bone marrow. It is concluded that the marrow stromal cells transduced with IL-3/IL-6 cDNA improve the hematopoiesis in allo-BMT mice. Co-graft with QXMSC1IL-3/IL-6 cells has synergistic effect in accelerating hematopoietic reconstitution.

[The improving effect of bone marrow stromal cell transfected with IL-3 gene on hematopoietic reconstitution in bone marrow transplantation of mice].

To study the improving effect of regulatable gene of IL-3 engineered bone marrow stromal cell on the hematopoietic reconstitution in allogeneic bone marrow transplantation, an inducible gene expression system was established in a bone marrow stromal cell line which expressed IL-3 gene induced by doxycycline (Dox). The lethally irradiated mice C57BL/6 (H-2(d)) were co-transplanted with allogeneic bone marrow (BALB/c, H-2(d), 1 x 10(7)/mice) in which T cell were depleted by monoclonal antibody anti-Thy1.2 added with complement and the gene engineered stromal cell QXMSC1tet-on + IL-3 (5 x 10(5)/mice) at the same time. Dox was administrated continuously for 15 days to induce the expression of IL-3. The hematopoiesis in the bone marrow transplanted mice were observed at 30, 60 days post-transplantation, respectively. The numbers of RBC and WBC in peripheral blood were counted, and nucleated cells, CFU-S, CFU-GM, CFU-E and CFU-GEMM were measured in recipient bone marrow. The results showed that the engineered stromal cell line achieved high-level and controllable IL-3 expression. Co-graft with QXMSC1tet-on + IL-3 significantly increased the number of RBC, WBC in recipient peripheral blood, and the nucleated cells, CFU-S, CFU-GM, CFU-E, CFU-GEMM in bone marrow, compared with those coinfused with QXMSC1 or QXMSC1tet-on-TRE as control. In conclusion, regulatable gene IL-3 engineered bone marrow stromal cells accelerates hematopoietic reconstitution after allogeneic bone marrow transplantation.