The coding sequence of Vitreoscilla hemoglobin (vhb) was cloned with PCR technique from Vitreoscilla stercoraria Pringsheim. The plant expression vector with vhb gene under the control of CaMV 35S promoter was constru...The coding sequence of Vitreoscilla hemoglobin (vhb) was cloned with PCR technique from Vitreoscilla stercoraria Pringsheim. The plant expression vector with vhb gene under the control of CaMV 35S promoter was constructed and used in the transformation of Petunia hybrida Vilm by the Agrobacterium mediated procedure. The results of PCR amplification and Southern hybridization indicated that the vhb gene had been integrated into the petunia genome and the vhb gene expression had been detected by RT-PCR amplification. In hydroponic culture the transgenic petunias grew much better than non-transgenic controls. For further analysis of hypoxia tolerance of transgenic petunia, the petunia plants with vhb gene were submerged into liquid MS medium. The transgenic plants survived in hypoxic condition and grew out of the liquid surface in a few weeks, while non-transgenic plants were still submerged and suffocated in culture solution without ability to grow out of liquid medium in submersed culture for four to five weeks. The vhb gene transformed petunia plants had been planted and tested in a simulated flooding condition, and showed obvious tolerance to water-logging. It seen is that hemoglobin gene from Vitreoscilla might have the potential use in molecular breeding for the improvement of plant resistance to hypoxia and flooding.展开更多
Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have pre...Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.展开更多
文摘The coding sequence of Vitreoscilla hemoglobin (vhb) was cloned with PCR technique from Vitreoscilla stercoraria Pringsheim. The plant expression vector with vhb gene under the control of CaMV 35S promoter was constructed and used in the transformation of Petunia hybrida Vilm by the Agrobacterium mediated procedure. The results of PCR amplification and Southern hybridization indicated that the vhb gene had been integrated into the petunia genome and the vhb gene expression had been detected by RT-PCR amplification. In hydroponic culture the transgenic petunias grew much better than non-transgenic controls. For further analysis of hypoxia tolerance of transgenic petunia, the petunia plants with vhb gene were submerged into liquid MS medium. The transgenic plants survived in hypoxic condition and grew out of the liquid surface in a few weeks, while non-transgenic plants were still submerged and suffocated in culture solution without ability to grow out of liquid medium in submersed culture for four to five weeks. The vhb gene transformed petunia plants had been planted and tested in a simulated flooding condition, and showed obvious tolerance to water-logging. It seen is that hemoglobin gene from Vitreoscilla might have the potential use in molecular breeding for the improvement of plant resistance to hypoxia and flooding.
基金This work was supported by National Natural Science Foundation of China(No.30671945)Science and Technology Commission of Shanghai Municipality(Nos.06JC14044,05ZR14055,054319928,04DZ14902)+2 种基金Shanghai Municipal Education(No.05BZ26)Shanghai Leading Academic Discipline Project(T0206)Science Foundation of Shanghai Institute of Immunology(No.07-A04,to Ningli Li).
文摘Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.
