1.Genotyping and preparation of the recombinant nucleocapsid protein antigen of hantavirus
JQ TANG ; M CAO ; T TANG ; CJ WANG ; CB WEI ; WL LEI
Chinese Medical Journal 2001;114(10):1030-1034
Objective To identify new recombinant antigens with potential for diagnosis of hemorrhagic fever with renal syndrom (HFRS) and establish reverse transcription-polymerase chain reaction-restriction fragments length polymorphism (RT-PCR-RFLP) for genotyping of hantavirus. Methods One group of primers was used to clone the full-length S genome segment and the partial S genorme segment of the N-terminal. The two cloned genes were both fusionally expressed and non fusionally expressed in the T7 system. The other group of primers was used to establish a RT-PCR method to detect RNAs in 37 virus isolates, 2 positive standard virus strains of hantavirus and 5 negative controls. The method for typing RFLP was set up by digesting the PCR products of 20 virus isolates with Ras Ⅰ and Hind Ⅲ. Results The non-fusionally expressed products with a working concentration of 1:10 000 by chapping enzyme-linked immunosorbent assay (cELISA), presented good biological activity though yields were lower than that of the fusionally expressed products.The specific component of the hantavirus genome (299 bp or 577 bp) wes seen in all viral samples. The genotyping of hantavirus showed that 9 out of the total were hantann (HTN) viruses, 8 were seol (SEO) viruses and 3 were not determined. Conclusions The good working titrer of expressed recombinant antigen showed that it has the potential to replace the natural antigen for detecting hantavirus antibodies. On comparison with cELISA, the detection rates for these two methods were 100% and 84.6%, and the coincidence rate was 84.6%. The former had a 15.4% higher sensitivity than the latter. The typing efficiency of RT-PCR-RFLP and sero-typing method was 85% (17/20) and 55% (11/20), respectively, showing that the former was 30% higher than the latter, while their results were highly consistant.
2.Intravascular local gene transfer mediated by protein-coated metallic stent
JQ YUAN ; RL GAO ; RW SHI ; LF SONG ; J TANG ; YL LI ; CJ TANG ; L MENG ; WM YUAN ; ZJ CHEN
Chinese Medical Journal 2001;114(10):1043-1045
Objective To assess the feasibility, efficiency and selectivity of adenovirus-mediated gene transfer to local arterial wall by protein-coated metallic stent. Methods A replication-defective recombinant adenovirus carrying the Lac Z reporter gene for nuclear specific β-galactosidase (Ad-βgal) was used in this study. The coating for metallic stent was made by immersing it in a gelatin solution containing crosslinker. The coated stents were mounted on a 4.0 or 3.0 mm percutaneous transluminal coronary angioplasty (PTCA) balloon and submersed into a high-titer Ad-βgal viral stock (2 × 1010 pfu/ml) for 3 min, and then implanted into the carotid artedes in 4 mini-swines and into the left anterior descending branch of the coronary artery in 2 mini-swines via 8F large lumen guiding catheters. The animals were sacrificed 7 (n=4), 14 (n = 1) and 21 (n = 1 ) days after implantation, respectively. The β-galactosidase expression was assessed by X-gal staining. Results The results showed that the expression of transgene was detected in all animal. In 1 of carotid artery with an intact intima, the β-gal expression was limited to endothelial cells. In vessels with denuded endothelium, gene expression was found in the sub-intima, media and adventitia. The transfection efficiency of medial smooth muscle cells was 38.6%. In 2 animals sacrificed 7 days after transfection, a microscopic examination of X-gal-stained samples did not show evidence of transfection in remote organs and arterial segments adjacent to the treated arterial site. Conclusions Adenovirus-mediated arterial gene transfer to endothelial, smooth muscle cells and adventitia by protein-coated metallic stent is feasible. The transfection efficiency is higher. The coated stent may act as a good carrier of adenovirus-mediated gene transfer and have a potential to prevent restenosis following PTCA.