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Objective@#To investigate the toxic effect of HIV-1 Vpr protein on neurons.@*Methods@#HIV-1 vpr gene was amplified by nested PCR in four parts of peripheral spleen (SPL) and central nervous tissue meninges (MG) of HIV-associated dementia (HAD) patients and non-HAD patients. Eukaryotic expression vector pEGFP-N1-vpr was constructed. The gene sequence and key amino acid sites were analyzed by BLAST and MEGA6. The expression of Vpr protein in N2a cells was detected by Western-blotting. The effects of Vpr proteins from different sources on the activity and cell cycle of N2a cells were studied by flow cytometry.@*Results@#HIV-1 vpr gene was successfully amplified by PCR. Sequence analysis showed that the vpr gene sequence belonged to HIV-1B subtype. There were amino acid mutations at C-terminal 84, 86 and 87 sites of central Vpr protein from HAD and non-HAD patients. Vpr protein could inhibit the activity of nerve cells, leading to G2 phase arrest. Different sources of Vpr had different intensity of action. Compared with other groups, Vpr protein from the meninges of HAD patients showed stronger inhibition of cell activity and G2 phase arrest ability.@*Conclusions@#Variations in key amino acid sites of Vpr protein could cause significant changes in its biological functions, and its significance in the pathogenesis of HAD remains to be further studied.
ABSTRACT
Objective@#BG-derived HIV-1 Tat protein from an HIV-associated dementia (HAD) patient was expressed in E. coli BL21(DE3) and purified in order to research the effects on human umbilical vein endothelial cells (HUVECs) activity.@*Methods@#The recombinant plasmid pGEX-KG-tat with HIV-1 tat stored in our laboratory was amplified by PCR. The PCR product was cloned into pET-32a-tat. The recombinant plasmid pET-32a-tat was transfected into E. coli, and Tat protein was expressed in BL21(DE3), which was induced by IPTG. Then it was purified by Ni-chelating chromatography column and gel filtration preloaded column, and identified by SDS-PAGE and Western blot(WB). The concentration was determined by BCA Kit. Different concentrations of Tat were added into HUVECs to detect their effects on cell activity by cck-8.@*Results@#The Tat with high purity was efficiently expressed in BL21 (DE3) and obtained by using the Ni-chelating chromatography column and gel filtration preloaded column. The concentration was 0.47 mg/ml by using BCA Kit. As the concentration of Tat increased, HUVECs activity decreased. There was no significant difference in cells viability between negative control with 100 ng/ml and 200 ng/ml group (P>0.05). There was significant difference in cells viability between negative control with 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group (P<0.05). But the difference between 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group was not statistically significant (P>0.05).@*Conclusions@#The HIV-1 Tat with biological activity was efficiently expressed in BL21 (DE3), and the activity of HUVECs was significantly decreased when the concentration reached 300 ng/ml.
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Objective@#To study the hepatitis B infection and immune status of the first-year students in a university and to provide evidence for the hepatitis B prevention in the university.@*Methods@#Subjects were the first-year students in a university; questionnaires were distributed. Enzyme-linked immunosorbent assay (ELISA) was adopted to test HBsAg and anti-HBs in serum.@*Results@#The hepatitis B vaccine inoculation rate was 80.8% among 728 subjects, the inoculation rate of urban students was higher than that of rural students (P<0.005). The HBsAg positive rate was 3.4%, no significant difference was found among students in cities and countryside. The anti-HBs positive rate was 65.2%, the positive rate of urban students was higher than that of rural students (P<0.005). The positive rate of anti-HBs in students with hepatitis B vaccination history was significantly higher than that of students without history of vaccination against hepatitis B. No significant differences were found between male and female students for all the groups.@*Conclusions@#By combining the condition of inoculation history of the first-year students in the university and the testresult of HBsAg and anti-HBs, it is necessary to strengthen vaccination against hepatitis B. The prevention of hepatitis B and inoculation of hepatitis B vaccine in the countryside should be strengthened.