Objective To investigate the suppressive effect of bone marrow stromal cells modified by CTLA4Ig-gene on lymphocyte activation. Methods The expressions of CTLA4Ig-gene at transcription level and protein level were assessed by RT-PCR, immunohistochemical techniques and Dot-ELISA. The suppressive effect of CTLA4Ig on lymphocyte activation was investigated in MLR system through MTT and ELISA which quantified IL-2 level. Results The transcription of CTLA4Ig-gene could be detected by RT-PCR in the transfected group and in the passage number two. Immunohistochemistry indicated that CTLA4Ig expression was diffusely located in the cytoplasm of BMSCs. Dot-ELISA could detect the expressed CTA4Ig in the culture medium at 12h and even in culture medium of the passage number l after transfection. MLR system showed that CTLA4Ig had significant inhibition on lymphocyte proliferation and IL-2 secretion. Conclusion Ad-CTLA4Ig could transfect BMSCs efficiently. Morever, CTLA4Ig can suppress lymphocyte activation and IL-2 production.

Objective To investigate the possible effects on radiosensitivity in human umbilical vein endothelial cells after transfection of pcDNA3.1+Ape1 plasmid. Methods The expressing vector pcDNA3.1+ Ape1, the control vector pcDNA3.1+or non-transfection cells was irradiated by 2, 4, 6, and 8 Gy photon beam at 48 h post-transfection. The value of initial and residual Oliver tail moment (OTM) under the alkaline single cell gelelectrophoresis assay and the colony forming test were utilized as the markers for the evaluaton of cells intrinsic radiosensitivity. The effect on radiosensitivity in human umbilical vein endothelial cells after transfection of the expressing vector pcDNA3.1+Ape1 was analyzed according to the radio-dose, compared to the empty vecor control and non-transfection cells. Results The initial and residual OTM value of endothelial cells transfected by 3 μg pcDNA3.1+Ape1 plasmid was lower significantly than ones of endothelial cells untransfected at 2 Gy irradiation (P<0.01), but was no significant difference at 8 Gy (P>0.05), and SF2 was higher remarkably in transfected cells than one in untransfected cells (P<0.05), but SF4, SF6 and SF8 were no significant differences (all of P>0.05). Conclusions The transfection of pcDNA3.1+Ape1 plasmid could enhance radioresistance of endothelial cells to the low-dose irradiation.