Background The 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 inve...Background The 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.Methods According to CD28 gene sequence, we designed and synthysized three different siRNAs ( siRNA-1,siRNA-2, siRNA-3 ) containing 21 bases using SilencerTM 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 semiquantitative 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.Results Three 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 展开更多
文摘Background The 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.Methods According to CD28 gene sequence, we designed and synthysized three different siRNAs ( siRNA-1,siRNA-2, siRNA-3 ) containing 21 bases using SilencerTM 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 semiquantitative 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.Results Three 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