AIM: To detect the expression of mitochondrial uncoupling protein 2 (UCP2) in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.METHODS: Fifteen colon tis...AIM: To detect the expression of mitochondrial uncoupling protein 2 (UCP2) in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.METHODS: Fifteen colon tissue samples and 15 its adjacent tissue samples were obtained from colon cancer patients during surgical interventions. UCP2 expression was detected with immunohistochemical method in 10 normal controls, 10 hyperplastic polyp patients, 20 tubular adenoma patients and 78 colon cancer patients. Patients with rectal cancer were excluded. Quantitative reverse transcription polymerase chain reaction and Western blotting were used to detect UCP2 expressions in colon cancer tissue samples and its adjacent tissue samples. Relation between UCP2 expression and clinical pathological features of colon cancer was also analyzed. RESULTS: The UCP2 mRNA expression level was fourfold higher in colon cancer tissue samples than in its adjacent tissue samples. The UCP2 protein expression level was three-fold higher in colon cancer tissue samples than in its adjacent normal tissue samples. The UCP2 was mainly expressed in cytoplasm. The UCP2 was not expressed in normal colon mucosa. Strong positive staining for UCP2 with a diffuse distribution pattern was identified throughout the mucosa in colon cancer tissue samples with a positive expression rate of 85.9%. The UCP2 expression level was higher in colon cancer tissue samples at clinical stages Ⅲ and Ⅳ than in those at stageⅠ+ Ⅱ. Univariate analysis showed that the high UCP2 expression level was significantly correlated to colon cancer metastasis (hazard ratio = 4.321, confidence interval = 0.035-0.682, P = 0.046). CONCLUSION: UCP2 is highly expressed in human colon cancer tissue and may be involved in colon cancer metastasis.展开更多
Objective To study the activities of interleukin （IL）-2 and granulocyte-macrophage colony-stimulating factor （GM-CSF） （hlL-2/mGM-CSF）. Methods SOE PCR was used to change the linker of the fusion protein for high...Objective To study the activities of interleukin （IL）-2 and granulocyte-macrophage colony-stimulating factor （GM-CSF） （hlL-2/mGM-CSF）. Methods SOE PCR was used to change the linker of the fusion protein for higher activities. The fusion protein was expressed in Escherichia coli （E. coil） BL21 （DE3） in inclusion body （IB） form. After IB was extracted and clarified, it was denatured and purified by affinity chromatography. The protein was refolded by dilution in a L-arginine refolding buffer and refined by anion chromatography. The protein activity was detected by cytokine-dependent cell proliferation assay. Results The expression of hIL-2/mGM-CSF in E. coli yielded approximately 20 mg protein/L culture and the purity was about 90%. The specific activities of IL-2 and GM-CSF were 5.4×10^6 IU/mg and 7.1×10^6 IU/mg, respectively. Conclusion This research provides important information about the anti-tumor activity of hIL-2/mGM-CSF in vivo, thus facilitating future clinical research on hlL-2/mGM-CSF used in immune therapy.展开更多
Objective:To coastruct a strain of recombinant Mycobacterium smegmatis expressing the heat shock protein 65(Hsp65) and human interleukin 2(IL-2) fusion protein(rMS-Hsp65/IL-2) and to explore the effect of this constru...Objective:To coastruct a strain of recombinant Mycobacterium smegmatis expressing the heat shock protein 65(Hsp65) and human interleukin 2(IL-2) fusion protein(rMS-Hsp65/IL-2) and to explore the effect of this construct on lymphocyte function in mice.Methods:The fusion gene encoding Hsp65-hIL-2 was cloned into shuttle vector pSMT3.The recombinant plasmid pSMT3- Hsp65-hIL-2 was transferred to Mycobacterium smegmatis by electroporation.Positive clones were selected by hygromycin and identified by PCR.The expression of fusion protein Hsp65- hIL-2 was verified using indirect immunofluorescence staining.Mice were immunized for two times by subcutaneously injection with 1×10~6 CFU rMS-Hsp65/IL-2 at a three-week interval.Two weeks after the second immunization,mice were sacrificed and the serum samples were collected for determination of anli-Hsp65 specific IgG.Splenic lymphocytes were isolated and treated with the rMS-Hsp65/IL-2 to determine lymphocytic proliferation activity by MTT assay.IFN-γand IL-2 in the medium of the treated cells were also determined by ELISA.Results:Successful construction of rMS-Hsp65/IL-2 was verified by PCR and immunofluorescence staining.Compared to the splenic lymphocytes isolated from mice immunized with Bacille Calmette-Guerin or mice immunized with Mycobacterium smegmatis alone,the splenic lymphocytes isolated from mice immunized with rMS-Hsp65/IL-2 showed a marked increase in the proliferation of lymphocytes, together with an increased production of important cytokines such as IFN- 7 and IL-2. Conclusions:rMS-Hsp65/IL-2 markedly enhances lymphocyte function.Therefore,the fusion protein generated by rMS-Hsp65/lL-2 may be of potential value in generating an effective vaccine against tuberculosis.展开更多
Mitochondrial dysfunction is a significant pathological alte ration that occurs in Parkinson's disease(PD),and the Thr61lle(T61I)mutation in coiled-coil helix coiled-coil helix domain containing 2(CHCHD2),a crucia...Mitochondrial dysfunction is a significant pathological alte ration that occurs in Parkinson's disease(PD),and the Thr61lle(T61I)mutation in coiled-coil helix coiled-coil helix domain containing 2(CHCHD2),a crucial mitochondrial protein,has been reported to cause Parkinson's disease.FIFO-ATPase participates in the synthesis of cellular adenosine triphosphate(ATP)and plays a central role in mitochondrial energy metabolism.However,the specific roles of wild-type(WT)CHCHD2 and T611-mutant CHCHD2 in regulating F1FO-ATPase activity in Parkinson's disease,as well as whether CHCHD2 or CHCHD2 T61I affects mitochondrial function through regulating F1FO-ATPase activity,remain unclea r.Therefore,in this study,we expressed WT CHCHD2 and T61l-mutant CHCHD2 in an MPP^(+)-induced SH-SY5Y cell model of PD.We found that CHCHD2 protected mitochondria from developing MPP^(+)-induced dysfunction.Under normal conditions,ove rexpression of WT CHCHD2 promoted F1FO-ATPase assembly,while T61I-mutant CHCHD2 appeared to have lost the ability to regulate F1FO-ATPase assembly.In addition,mass spectrometry and immunoprecipitation showed that there was an interaction between CHCHD2 and F1FO-ATPase.Three weeks after transfection with AAV-CHCHD2 T61I,we intraperitoneally injected 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine into mice to establish an animal model of chronic Parkinson's disease and found that exogenous expression of the mutant protein worsened the behavioral deficits and dopaminergic neurodegeneration seen in this model.These findings suggest that WT CHCHD2 can alleviate mitochondrial dysfunction in PD by maintaining F1F0-ATPase structure and function.展开更多
The recombinant DNA techniques are used to construct a fusion protein PBVIL-2/PS-9 which contains gene fragments encoding human IL-2 and a murine single chain antibody (scFv) against human adenocarcinoma. The expressi...The recombinant DNA techniques are used to construct a fusion protein PBVIL-2/PS-9 which contains gene fragments encoding human IL-2 and a murine single chain antibody (scFv) against human adenocarcinoma. The expression differs from previous reports. It has been expressed as cytoplasmic bodies in E. colt. A high level expression at a level of 40% of total bacterlal proteins is obtained. The fusion protein possesses both the antigen binding characteristics of the parental mAB PS-9 and the bioactivity of IL-2.展开更多
Objective: To explore the mechanisms of microRNA-150, cyclin B1 and mitochondrial-associated protein 2 in regulating the apoptosis and inhibiting the invasion and migration of Huh-7 cells. Methods: Huh-7 cells were di...Objective: To explore the mechanisms of microRNA-150, cyclin B1 and mitochondrial-associated protein 2 in regulating the apoptosis and inhibiting the invasion and migration of Huh-7 cells. Methods: Huh-7 cells were divided into the control group, the negative control group (NC group) and the miR-150 overexpression group (mimic group). The miR-150 overexpressing cell line was constructed by plasmid transfection. The cell viability and apoptosis were detected by cell counting kit-8 and flow cytometry. The cell migration and invasion capacity were measured by cell wound scratch assay and Transwell. The levels of miRNA and mRNA were detected by real-time quantitative polymerase chain reaction and the relative expression levels of proteins were detected by Western blot. Results: MiR-150 significantly inhibited the cell viability of Huh-7 and promoted its apoptosis (P<0.01). After 24 h of cultivation, the mobility of the control group and the NC group were (83.54±4.66)%and (85.57±4.74)%, respectively. The mobility of the mimic group was (49.63±3.78)%, which was significantly lower than that of the control group and the NC group (P<0.01). After 24 h of cultivation, the invasive rate of the control group and the NC group were (100.56±2.87)%and (101.63±3.74)%, respectively, and the invasive rate of mimic group was (51.63±5.32)%, which was significantly lower than that of the control group and the NC group (P<0.01). The expression levels of cyclin B1 protein and mRNA in the mimic group were significantly lower than those in the control group and the NC group (P<0.01), and the level of mitochondrial-associated protein 2 in the mimic group was significantly higher than that in the control group and the NC group (P<0.01). Conclusions: MiR-150 may inhibit the proliferation, migration, invasion and apoptosis of hepatoma carcinoma cell by regulating cyclin B1 or up-regulating mitochondrial-associated protein 2 levels.展开更多
BACKGROUND:Disturbance of mitochondrial fi ssion and fusion(termed mitochondrial dynamics)is one of the leading causes of ischemia/reperfusion(I/R)-induced myocardial injury.Previous studies showed that mitochondrial ...BACKGROUND:Disturbance of mitochondrial fi ssion and fusion(termed mitochondrial dynamics)is one of the leading causes of ischemia/reperfusion(I/R)-induced myocardial injury.Previous studies showed that mitochondrial aldehyde dehydrogenase 2(ALDH2)conferred cardioprotective effect against myocardial I/R injury and suppressed I/R-induced excessive mitophagy in cardiomyocytes.However,whether ALDH2 participates in the regulation of mitochondrial dynamics during myocardial I/R injury remains unknown.METHODS:In the present study,we investigated the effect of ALDH2 on mitochondrial dynamics and the underlying mechanisms using the H9c2 cells exposed to hypoxia/reoxygenation(H/R)as an in vitro model of myocardial I/R injury.RESULTS:Cardiomyocyte apoptosis was significantly increased after oxygen-glucose deprivation and reoxygenation(OGD/R),and ALDH2 activation largely decreased the cardiomyocyte apoptosis.Additionally,we found that both ALDH2 activation and overexpression significantly inhibited the increased mitochondrial fission after OGD/R.Furthermore,we found that ALDH2 dominantly suppressed dynamin-related protein 1(Drp1)phosphorylation(Ser616)and adenosine monophosphate-activated protein kinase(AMPK)phosphorylation(Thr172)but not interfered with the expression levels of mitochondrial shaping proteins.CONCLUSIONS:We demonstrate the protective effect of ALDH2 against cardiomyocyte H/R injury with a novel mechanism on mitochondrial fission/fusion.展开更多
Three pairs of specific primers were designed to amplify the F2-1, F2-2 and XF2-2 truncated sequences of ORF2 which encodes the capsid protein of porcine circovirus type 2 (PCV-2). The F2-1 sequence had most of the NL...Three pairs of specific primers were designed to amplify the F2-1, F2-2 and XF2-2 truncated sequences of ORF2 which encodes the capsid protein of porcine circovirus type 2 (PCV-2). The F2-1 sequence had most of the NLS region of ORF2, but the F2-2 and XF2-2 genes had the NLS region deleted. Truncated genes were subcloned into pET-32a(+) vectors to construct recombinant fusion expression vectors. The vectors were then transformed into Rosetta(DE3) E. coli and expressed by induction of IPTG. Expressed proteins were detected by western blotting and ELISA. The protein with best immunoreactivity was confirmed and selected, then utilized to inoculate SPF rabbits to prepare polyclonal antibodies. The protein and prepared polyclonal antibody were utilized to detect sera samples against PCV-2 from Shandong province and PCV-2 particles in PK-15 cells. In our study, three recombinant fusion proteins were successfully obtained, and the molecular weights of fusion proteins were 35.9 kDa, 33.6 kDa and 38.6 kDa respectively detected by SDS-PAGE. All of the proteins showed positive reaction with anti-PCV-2 antisera, and His-XF2-2 showed better immunoreactivity than the others. The protein of His-XF2-2 was coated as antigen in ELISA to detect the seroprevalence of PCV-2 in certain districts of Shandong province, the seropositivity rate was 27.7 % (73/264). Specific fluorescence and positive signals for PCV-2 could be detected in PK-15 cells inoculated with PCV-2 with the participation of prepared antibodies against His-XF2-2 in IFA and IPMA. Experimental results indicated that the truncated PCV-2 ORF2 gene containing most of the NLS region was successfully expressed in E. coli, and His-XF2-2 was demonstrated to have better immunoreactivity with anti-PCV-2 antisera than the other two fusion proteins. His-XF2-2 and prepared polyclonal antibodies against it had a satisfactory capability in detecting PCV-2 infection.展开更多
基金Supported by Scientific Research Fund from Jiangsu Province,No.BK2006243National Natural Science Foundation of China,No.30771039
文摘AIM: To detect the expression of mitochondrial uncoupling protein 2 (UCP2) in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.METHODS: Fifteen colon tissue samples and 15 its adjacent tissue samples were obtained from colon cancer patients during surgical interventions. UCP2 expression was detected with immunohistochemical method in 10 normal controls, 10 hyperplastic polyp patients, 20 tubular adenoma patients and 78 colon cancer patients. Patients with rectal cancer were excluded. Quantitative reverse transcription polymerase chain reaction and Western blotting were used to detect UCP2 expressions in colon cancer tissue samples and its adjacent tissue samples. Relation between UCP2 expression and clinical pathological features of colon cancer was also analyzed. RESULTS: The UCP2 mRNA expression level was fourfold higher in colon cancer tissue samples than in its adjacent tissue samples. The UCP2 protein expression level was three-fold higher in colon cancer tissue samples than in its adjacent normal tissue samples. The UCP2 was mainly expressed in cytoplasm. The UCP2 was not expressed in normal colon mucosa. Strong positive staining for UCP2 with a diffuse distribution pattern was identified throughout the mucosa in colon cancer tissue samples with a positive expression rate of 85.9%. The UCP2 expression level was higher in colon cancer tissue samples at clinical stages Ⅲ and Ⅳ than in those at stageⅠ+ Ⅱ. Univariate analysis showed that the high UCP2 expression level was significantly correlated to colon cancer metastasis (hazard ratio = 4.321, confidence interval = 0.035-0.682, P = 0.046). CONCLUSION: UCP2 is highly expressed in human colon cancer tissue and may be involved in colon cancer metastasis.
基金supported by the National Natural Science Foundation of China (30771952)the National Natural Science Foundation of Guangdong Province (07117783)NSFC and the Research Grants Council of Hong Kong Joint Research Scheme (30418003).
文摘Objective To study the activities of interleukin （IL）-2 and granulocyte-macrophage colony-stimulating factor （GM-CSF） （hlL-2/mGM-CSF）. Methods SOE PCR was used to change the linker of the fusion protein for higher activities. The fusion protein was expressed in Escherichia coli （E. coil） BL21 （DE3） in inclusion body （IB） form. After IB was extracted and clarified, it was denatured and purified by affinity chromatography. The protein was refolded by dilution in a L-arginine refolding buffer and refined by anion chromatography. The protein activity was detected by cytokine-dependent cell proliferation assay. Results The expression of hIL-2/mGM-CSF in E. coli yielded approximately 20 mg protein/L culture and the purity was about 90%. The specific activities of IL-2 and GM-CSF were 5.4×10^6 IU/mg and 7.1×10^6 IU/mg, respectively. Conclusion This research provides important information about the anti-tumor activity of hIL-2/mGM-CSF in vivo, thus facilitating future clinical research on hlL-2/mGM-CSF used in immune therapy.
基金funded by the National Natural Science Eoundation of China(Grant ID:30972767)
文摘Objective:To coastruct a strain of recombinant Mycobacterium smegmatis expressing the heat shock protein 65(Hsp65) and human interleukin 2(IL-2) fusion protein(rMS-Hsp65/IL-2) and to explore the effect of this construct on lymphocyte function in mice.Methods:The fusion gene encoding Hsp65-hIL-2 was cloned into shuttle vector pSMT3.The recombinant plasmid pSMT3- Hsp65-hIL-2 was transferred to Mycobacterium smegmatis by electroporation.Positive clones were selected by hygromycin and identified by PCR.The expression of fusion protein Hsp65- hIL-2 was verified using indirect immunofluorescence staining.Mice were immunized for two times by subcutaneously injection with 1×10~6 CFU rMS-Hsp65/IL-2 at a three-week interval.Two weeks after the second immunization,mice were sacrificed and the serum samples were collected for determination of anli-Hsp65 specific IgG.Splenic lymphocytes were isolated and treated with the rMS-Hsp65/IL-2 to determine lymphocytic proliferation activity by MTT assay.IFN-γand IL-2 in the medium of the treated cells were also determined by ELISA.Results:Successful construction of rMS-Hsp65/IL-2 was verified by PCR and immunofluorescence staining.Compared to the splenic lymphocytes isolated from mice immunized with Bacille Calmette-Guerin or mice immunized with Mycobacterium smegmatis alone,the splenic lymphocytes isolated from mice immunized with rMS-Hsp65/IL-2 showed a marked increase in the proliferation of lymphocytes, together with an increased production of important cytokines such as IFN- 7 and IL-2. Conclusions:rMS-Hsp65/IL-2 markedly enhances lymphocyte function.Therefore,the fusion protein generated by rMS-Hsp65/lL-2 may be of potential value in generating an effective vaccine against tuberculosis.
基金supported by the National Natural Science Foundation of China(Youth Program),No.81901282(to XC)the National Natural Science Foundation of China,Nos.81401416(to PX),81870992(to PX),81870856(to XC and MZ)+3 种基金Guangdong Basic and Applied Basic Research Foundation the Science Foundation,No.2019A1515011189(to XC)Central Government Guiding Local Science and Technology Development Projects,No.ZYYD2022C17(to PX)Key Project of Guangzhou Health Commission,No.2019-ZD-09(to PX)Science and Technology Planning Project of Guangzhou,Nos.202102020029(to XC),202102010010(to PX)。
文摘Mitochondrial dysfunction is a significant pathological alte ration that occurs in Parkinson's disease(PD),and the Thr61lle(T61I)mutation in coiled-coil helix coiled-coil helix domain containing 2(CHCHD2),a crucial mitochondrial protein,has been reported to cause Parkinson's disease.FIFO-ATPase participates in the synthesis of cellular adenosine triphosphate(ATP)and plays a central role in mitochondrial energy metabolism.However,the specific roles of wild-type(WT)CHCHD2 and T611-mutant CHCHD2 in regulating F1FO-ATPase activity in Parkinson's disease,as well as whether CHCHD2 or CHCHD2 T61I affects mitochondrial function through regulating F1FO-ATPase activity,remain unclea r.Therefore,in this study,we expressed WT CHCHD2 and T61l-mutant CHCHD2 in an MPP^(+)-induced SH-SY5Y cell model of PD.We found that CHCHD2 protected mitochondria from developing MPP^(+)-induced dysfunction.Under normal conditions,ove rexpression of WT CHCHD2 promoted F1FO-ATPase assembly,while T61I-mutant CHCHD2 appeared to have lost the ability to regulate F1FO-ATPase assembly.In addition,mass spectrometry and immunoprecipitation showed that there was an interaction between CHCHD2 and F1FO-ATPase.Three weeks after transfection with AAV-CHCHD2 T61I,we intraperitoneally injected 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine into mice to establish an animal model of chronic Parkinson's disease and found that exogenous expression of the mutant protein worsened the behavioral deficits and dopaminergic neurodegeneration seen in this model.These findings suggest that WT CHCHD2 can alleviate mitochondrial dysfunction in PD by maintaining F1F0-ATPase structure and function.
文摘The recombinant DNA techniques are used to construct a fusion protein PBVIL-2/PS-9 which contains gene fragments encoding human IL-2 and a murine single chain antibody (scFv) against human adenocarcinoma. The expression differs from previous reports. It has been expressed as cytoplasmic bodies in E. colt. A high level expression at a level of 40% of total bacterlal proteins is obtained. The fusion protein possesses both the antigen binding characteristics of the parental mAB PS-9 and the bioactivity of IL-2.
文摘Objective: To explore the mechanisms of microRNA-150, cyclin B1 and mitochondrial-associated protein 2 in regulating the apoptosis and inhibiting the invasion and migration of Huh-7 cells. Methods: Huh-7 cells were divided into the control group, the negative control group (NC group) and the miR-150 overexpression group (mimic group). The miR-150 overexpressing cell line was constructed by plasmid transfection. The cell viability and apoptosis were detected by cell counting kit-8 and flow cytometry. The cell migration and invasion capacity were measured by cell wound scratch assay and Transwell. The levels of miRNA and mRNA were detected by real-time quantitative polymerase chain reaction and the relative expression levels of proteins were detected by Western blot. Results: MiR-150 significantly inhibited the cell viability of Huh-7 and promoted its apoptosis (P<0.01). After 24 h of cultivation, the mobility of the control group and the NC group were (83.54±4.66)%and (85.57±4.74)%, respectively. The mobility of the mimic group was (49.63±3.78)%, which was significantly lower than that of the control group and the NC group (P<0.01). After 24 h of cultivation, the invasive rate of the control group and the NC group were (100.56±2.87)%and (101.63±3.74)%, respectively, and the invasive rate of mimic group was (51.63±5.32)%, which was significantly lower than that of the control group and the NC group (P<0.01). The expression levels of cyclin B1 protein and mRNA in the mimic group were significantly lower than those in the control group and the NC group (P<0.01), and the level of mitochondrial-associated protein 2 in the mimic group was significantly higher than that in the control group and the NC group (P<0.01). Conclusions: MiR-150 may inhibit the proliferation, migration, invasion and apoptosis of hepatoma carcinoma cell by regulating cyclin B1 or up-regulating mitochondrial-associated protein 2 levels.
基金the National Key R&D Program of China(2017YFC0908700,2017YFC0908703)National Natural Science Foundation of China(81772036,81671952,81873950,81873953,81570401,81571934)+4 种基金National S&T Fundamental Resources Investigation Project(2018FY100600,2018FY100602)Taishan Pandeng Scholar Program of Shandong Province(tspd20181220)Taishan Young Scholar Program of Shandong Province(tsqn20161065,tsqn201812129)Key R&D Program of Shandong Province(2018GSF118003)the Fundamental Research Funds of Shandong University(2018JC011).
文摘BACKGROUND:Disturbance of mitochondrial fi ssion and fusion(termed mitochondrial dynamics)is one of the leading causes of ischemia/reperfusion(I/R)-induced myocardial injury.Previous studies showed that mitochondrial aldehyde dehydrogenase 2(ALDH2)conferred cardioprotective effect against myocardial I/R injury and suppressed I/R-induced excessive mitophagy in cardiomyocytes.However,whether ALDH2 participates in the regulation of mitochondrial dynamics during myocardial I/R injury remains unknown.METHODS:In the present study,we investigated the effect of ALDH2 on mitochondrial dynamics and the underlying mechanisms using the H9c2 cells exposed to hypoxia/reoxygenation(H/R)as an in vitro model of myocardial I/R injury.RESULTS:Cardiomyocyte apoptosis was significantly increased after oxygen-glucose deprivation and reoxygenation(OGD/R),and ALDH2 activation largely decreased the cardiomyocyte apoptosis.Additionally,we found that both ALDH2 activation and overexpression significantly inhibited the increased mitochondrial fission after OGD/R.Furthermore,we found that ALDH2 dominantly suppressed dynamin-related protein 1(Drp1)phosphorylation(Ser616)and adenosine monophosphate-activated protein kinase(AMPK)phosphorylation(Thr172)but not interfered with the expression levels of mitochondrial shaping proteins.CONCLUSIONS:We demonstrate the protective effect of ALDH2 against cardiomyocyte H/R injury with a novel mechanism on mitochondrial fission/fusion.
基金supported by the special studies for social welfare researches in institutes (2005DIB4J041)
文摘Three pairs of specific primers were designed to amplify the F2-1, F2-2 and XF2-2 truncated sequences of ORF2 which encodes the capsid protein of porcine circovirus type 2 (PCV-2). The F2-1 sequence had most of the NLS region of ORF2, but the F2-2 and XF2-2 genes had the NLS region deleted. Truncated genes were subcloned into pET-32a(+) vectors to construct recombinant fusion expression vectors. The vectors were then transformed into Rosetta(DE3) E. coli and expressed by induction of IPTG. Expressed proteins were detected by western blotting and ELISA. The protein with best immunoreactivity was confirmed and selected, then utilized to inoculate SPF rabbits to prepare polyclonal antibodies. The protein and prepared polyclonal antibody were utilized to detect sera samples against PCV-2 from Shandong province and PCV-2 particles in PK-15 cells. In our study, three recombinant fusion proteins were successfully obtained, and the molecular weights of fusion proteins were 35.9 kDa, 33.6 kDa and 38.6 kDa respectively detected by SDS-PAGE. All of the proteins showed positive reaction with anti-PCV-2 antisera, and His-XF2-2 showed better immunoreactivity than the others. The protein of His-XF2-2 was coated as antigen in ELISA to detect the seroprevalence of PCV-2 in certain districts of Shandong province, the seropositivity rate was 27.7 % (73/264). Specific fluorescence and positive signals for PCV-2 could be detected in PK-15 cells inoculated with PCV-2 with the participation of prepared antibodies against His-XF2-2 in IFA and IPMA. Experimental results indicated that the truncated PCV-2 ORF2 gene containing most of the NLS region was successfully expressed in E. coli, and His-XF2-2 was demonstrated to have better immunoreactivity with anti-PCV-2 antisera than the other two fusion proteins. His-XF2-2 and prepared polyclonal antibodies against it had a satisfactory capability in detecting PCV-2 infection.
