AIM: To improve the immunogenicity of receptor binding site of hepatitis B virus (HBV) on preS1 antigen using HBV core antigen as an immuno-carrier.METHODS: One to 6 tandem copies of HBV preS1 (21-47)fragment were ins...AIM: To improve the immunogenicity of receptor binding site of hepatitis B virus (HBV) on preS1 antigen using HBV core antigen as an immuno-carrier.METHODS: One to 6 tandem copies of HBV preS1 (21-47)fragment were inserted into HBcAg at the sites of aa 78 and 82, and expressed in E. coli. ELISA, Western blot and animal immunization were used to analyze the antigenicity and immmunogenicity of purified particulate antigens. The ability to capture HBV by antibodies elicited by chimeric partides was detected with immuno-capture PCR.RESULTS: Recombinant antigens CⅠ, CⅡ, CⅢ carrying 1-3 copies of HBV preS1 (21-47) individually could form viruslike particles (VLPs), similar to HBcAg in morphology. But recombinant antigens carrying 4-6 copies of HBV preS1 (21-47) were poorly expressed in E.coli. Chimeric antigens were lacking of immunoreactivity with anti-HBc monoclonal antibodies (McAbs), but still reserved good immunoreactivity with anti-HBe McAbs. CⅠ, CⅡ, CⅢ could strongly react with anti-preS1 McAb, suggesting that preS1 (21-47) fragment was well exposed on the surface of chimeric VLPs. Three chimeric VLP antigens (CⅠ, CⅡ and CⅢ) could stimulate mice to produce high-level antibody responses, and their immunogenicity was stronger than non-particulate antigen 21-47*6, containing 6 copies of preS1 (21-47). Mouse antibodies to CⅠ, CⅡ and CⅢ were able to capture HBV virions in immuno-capture PCR assay in vitro.CONCLUSION: Chimeric particulate antigens of receptor binding site-core antigen of HBV can elicit strong antibody responses to preS1. They have a potential to be developed into prophylactic or therapeutic vaccines against HBV infection.展开更多
Cre/loxP,a site-specific recombination system,has been widely used for various purposes,including chromosomal translocations,generation of marker-free transgenic plants,tissue-specific activation of a reporter gene an...Cre/loxP,a site-specific recombination system,has been widely used for various purposes,including chromosomal translocations,generation of marker-free transgenic plants,tissue-specific activation of a reporter gene and efficient heterologous gene expression in plants.However,stable or transient expression of Cre recombinase in plants can cause chlorosis or necrosis.Here,we describe a modified Cre/loxP recombination system using a DNA fragment flanked with loxP sites in the same orientation in which necrosis induced by Cre recombinase in Nicotiana benthamiana leaves was alleviated.The modified system was successfully used to create functional GFP-tagged pepper mild mottle virus(PMMoV)and a chimeric virus with coat protein(CP)substitution assembled from separate pro-vector modules.Our results provide a new strategy and flexible technique to construct chimeric virus and infectious clones for plant viruses with large genomes.展开更多
Classical swine fever （CSF）, a list A disease of Office International des Epizooties, is caused by classical swine fever virus （CSFV） belonging to the Flaviviridae family. The well-known lapinized Chinese strain o...Classical swine fever （CSF）, a list A disease of Office International des Epizooties, is caused by classical swine fever virus （CSFV） belonging to the Flaviviridae family. The well-known lapinized Chinese strain of CSFV, also known as C-strain, was developed in China in the mid-1950s. In the past half a century, the vaccine has been proved to be safe and immunogenic in pigs of essentially any age. It is of high efficacy, providing immunized animals with broad-spectrum, sometimes lifelong, protection, which is contributed by both cell-mediated immunity and humoral immunity, against essentially all genotypes or subgenotypes of the virus. The maternal antibodies derived from immunized sows can confer solid protection of their offspring from disease; however, they have been proved to inhibit the successful active immunization of C-strain vaccine. The complete genomes of C-strain and dozens of established or field strains have been sequenced and annotated. Recently, the reverse genetics system of C-strain has been developed, resulting in several C- strain-derived candidate marker vaccines. Many countries manage to control or even eradicate CSF with the aid of mass vaccination with C-strain. in spite of these efforts, the eradication of the disease worldwide remains a big challenge and needs to go a long way, and provably still resorts to genetically modified C-strain vaccine. The authors present an overview of the characteristics of the vaccine, which has stood the test of half a century.展开更多
Hepatitis B virus (HBV) infection seriously affects human health. Stable and reliable animal models of HBV infection bear significance in studying pathogenesis of this health condition and development of intervention ...Hepatitis B virus (HBV) infection seriously affects human health. Stable and reliable animal models of HBV infection bear significance in studying pathogenesis of this health condition and development of intervention measures. HBV exhibits high specificity for hosts, and chimpanzee is long used as sole animal model of HBV infection. However, use of chimpanzees is strictly constrained because of ethical reasons. Many methods were used to establish small-animal models of HBV infection. Tupaia is the only nonprimate animalthat can be infected by HBV. Use of HBV-related duck hepatitis virus and marmot hepatitis virus infection model contributed to evaluation of mechanism of HBV replication and HBV treatment methods. In recent years, development of human–mouse chimeric model provided possibility of using common experimental animals to carry out HBV research.These models feature their own advantages and disadvantages and can be complementary in some ways. This展开更多
The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown possibility.The indication of antiviral prophylaxis w...The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown possibility.The indication of antiviral prophylaxis with nucleo(t)side analogue is given according to the risk of HBV reactivation of the prescribed therapy.Though the advent of new drugs is occurring in all the field of medicine,in the setting of hematologic malignancies the last few years have been characterized by several drug classes and innovative cellular treatment.As novel therapies,there are few data about the rate of HBV reactivation and the decision of starting or not an antiviral prophylaxis could be challenging.Moreover,patients are often treated with a combination of different drugs,so evaluating the actual role of these new therapies in increasing the risk of HBV reactivation is difficult.First results are now available,but further studies are still needed.Patients with chronic HBV infection[hepatitis B surface antigen(HBsAg)positive]are reasonably all treated.Past/resolved HBV patients(HBsAg negative)are the actual area of uncertainty where it could be difficult choosing between prophylaxis and pre-emptive strategy.展开更多
为了构建猪圆环病毒1型(porcine circovirus type 1,PCV1)和猪圆环病毒3型(porcine circovirus type 3,PCV3)的嵌合病毒PCV1-3,并为PCV3疫苗研制奠定基础,该研究以PCV1基因组为骨架,将PCV1的ORF2基因替换为PCV3的ORF2基因,构建嵌合型猪...为了构建猪圆环病毒1型(porcine circovirus type 1,PCV1)和猪圆环病毒3型(porcine circovirus type 3,PCV3)的嵌合病毒PCV1-3,并为PCV3疫苗研制奠定基础,该研究以PCV1基因组为骨架,将PCV1的ORF2基因替换为PCV3的ORF2基因,构建嵌合型猪圆环病毒(PCV1-3)DNA克隆。PCR和序列测序结果显示,成功构建出了PCV1-3感染性克隆;将感染性克隆转染PK-15细胞,并将第4代病毒进行免疫过氧化物酶单层试验(IPMA)和蛋白免疫印迹(Western Blot)检测,结果显示成功拯救了重组病毒PCV1-3。对第4代病毒进行滴度测定,效价为105.13 TCID 50/mL。因此,该试验成功拯救出一种新型嵌合型病毒PCV1-3,并为进一步研究PCV3疫苗奠定了基础。展开更多
Hepatocellular carcinoma(HCC)is associated with high morbidity and mortality,and is prone to intra-and extrahepatic metastasis due to the anatomical and functional characteristics of the liver.Due to the complexity an...Hepatocellular carcinoma(HCC)is associated with high morbidity and mortality,and is prone to intra-and extrahepatic metastasis due to the anatomical and functional characteristics of the liver.Due to the complexity and high relapse rate associated with radical surgery or radiofrequency ablation,immune checkpoint inhibitors(ICIs)are increasingly being used to treat HCC.Several immunotherapeutic agents,along with their combinations,have been clinically approved to treat advanced or recurrent HCC.This review discusses the leading ICIs in practice and those currently undergoing randomized phase 1-3 trials as monotherapy or combination therapy.Furthermore,we summarize the rapidly developing alternative strategies such as chimeric antigen receptor-engineered T cell therapy and tumor vaccines.Combination therapy is a promising potential treatment option.These immunotherapies are also summarized in this review,which provides insights into the advantages,limitations,and novel angles for future research in establishing viable and alternative therapies against HCC.展开更多
Green fluorescent protein(GFP)gene was inserted into the pseudogene(ψ)region of genome of rabies virus rHep-Flury strain,and a recombinant rabies virus carrying GFP,designated as HEP-GFP,was rescued by reverse geneti...Green fluorescent protein(GFP)gene was inserted into the pseudogene(ψ)region of genome of rabies virus rHep-Flury strain,and a recombinant rabies virus carrying GFP,designated as HEP-GFP,was rescued by reverse genetics system.It was demonstrated that green fluorescent protein could be expressed in the chimeric virus after 5 passages in BHK-21 cell line.The research indicated that the pseudogene(ψ)region in the genome of rHEP-Flury strain,as an independent functional unit in the process of virus assembly,could independently carry and express exogenous genes.展开更多
基金Supported by the Excellent Scholar Incubation Plan of Ministry of Education, China
文摘AIM: To improve the immunogenicity of receptor binding site of hepatitis B virus (HBV) on preS1 antigen using HBV core antigen as an immuno-carrier.METHODS: One to 6 tandem copies of HBV preS1 (21-47)fragment were inserted into HBcAg at the sites of aa 78 and 82, and expressed in E. coli. ELISA, Western blot and animal immunization were used to analyze the antigenicity and immmunogenicity of purified particulate antigens. The ability to capture HBV by antibodies elicited by chimeric partides was detected with immuno-capture PCR.RESULTS: Recombinant antigens CⅠ, CⅡ, CⅢ carrying 1-3 copies of HBV preS1 (21-47) individually could form viruslike particles (VLPs), similar to HBcAg in morphology. But recombinant antigens carrying 4-6 copies of HBV preS1 (21-47) were poorly expressed in E.coli. Chimeric antigens were lacking of immunoreactivity with anti-HBc monoclonal antibodies (McAbs), but still reserved good immunoreactivity with anti-HBe McAbs. CⅠ, CⅡ, CⅢ could strongly react with anti-preS1 McAb, suggesting that preS1 (21-47) fragment was well exposed on the surface of chimeric VLPs. Three chimeric VLP antigens (CⅠ, CⅡ and CⅢ) could stimulate mice to produce high-level antibody responses, and their immunogenicity was stronger than non-particulate antigen 21-47*6, containing 6 copies of preS1 (21-47). Mouse antibodies to CⅠ, CⅡ and CⅢ were able to capture HBV virions in immuno-capture PCR assay in vitro.CONCLUSION: Chimeric particulate antigens of receptor binding site-core antigen of HBV can elicit strong antibody responses to preS1. They have a potential to be developed into prophylactic or therapeutic vaccines against HBV infection.
基金supported by the National Key R&D Program of China(2019YFD1001800)the China Agriculture Research System of MOF and MARA(CARS24-C-04)+1 种基金supported by the Science&Technology Public Welfare Project of Ningbo City,China(202002N3005)K.C.Wong Education Foundation,China。
文摘Cre/loxP,a site-specific recombination system,has been widely used for various purposes,including chromosomal translocations,generation of marker-free transgenic plants,tissue-specific activation of a reporter gene and efficient heterologous gene expression in plants.However,stable or transient expression of Cre recombinase in plants can cause chlorosis or necrosis.Here,we describe a modified Cre/loxP recombination system using a DNA fragment flanked with loxP sites in the same orientation in which necrosis induced by Cre recombinase in Nicotiana benthamiana leaves was alleviated.The modified system was successfully used to create functional GFP-tagged pepper mild mottle virus(PMMoV)and a chimeric virus with coat protein(CP)substitution assembled from separate pro-vector modules.Our results provide a new strategy and flexible technique to construct chimeric virus and infectious clones for plant viruses with large genomes.
文摘Classical swine fever （CSF）, a list A disease of Office International des Epizooties, is caused by classical swine fever virus （CSFV） belonging to the Flaviviridae family. The well-known lapinized Chinese strain of CSFV, also known as C-strain, was developed in China in the mid-1950s. In the past half a century, the vaccine has been proved to be safe and immunogenic in pigs of essentially any age. It is of high efficacy, providing immunized animals with broad-spectrum, sometimes lifelong, protection, which is contributed by both cell-mediated immunity and humoral immunity, against essentially all genotypes or subgenotypes of the virus. The maternal antibodies derived from immunized sows can confer solid protection of their offspring from disease; however, they have been proved to inhibit the successful active immunization of C-strain vaccine. The complete genomes of C-strain and dozens of established or field strains have been sequenced and annotated. Recently, the reverse genetics system of C-strain has been developed, resulting in several C- strain-derived candidate marker vaccines. Many countries manage to control or even eradicate CSF with the aid of mass vaccination with C-strain. in spite of these efforts, the eradication of the disease worldwide remains a big challenge and needs to go a long way, and provably still resorts to genetically modified C-strain vaccine. The authors present an overview of the characteristics of the vaccine, which has stood the test of half a century.
文摘Hepatitis B virus (HBV) infection seriously affects human health. Stable and reliable animal models of HBV infection bear significance in studying pathogenesis of this health condition and development of intervention measures. HBV exhibits high specificity for hosts, and chimpanzee is long used as sole animal model of HBV infection. However, use of chimpanzees is strictly constrained because of ethical reasons. Many methods were used to establish small-animal models of HBV infection. Tupaia is the only nonprimate animalthat can be infected by HBV. Use of HBV-related duck hepatitis virus and marmot hepatitis virus infection model contributed to evaluation of mechanism of HBV replication and HBV treatment methods. In recent years, development of human–mouse chimeric model provided possibility of using common experimental animals to carry out HBV research.These models feature their own advantages and disadvantages and can be complementary in some ways. This
文摘The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown possibility.The indication of antiviral prophylaxis with nucleo(t)side analogue is given according to the risk of HBV reactivation of the prescribed therapy.Though the advent of new drugs is occurring in all the field of medicine,in the setting of hematologic malignancies the last few years have been characterized by several drug classes and innovative cellular treatment.As novel therapies,there are few data about the rate of HBV reactivation and the decision of starting or not an antiviral prophylaxis could be challenging.Moreover,patients are often treated with a combination of different drugs,so evaluating the actual role of these new therapies in increasing the risk of HBV reactivation is difficult.First results are now available,but further studies are still needed.Patients with chronic HBV infection[hepatitis B surface antigen(HBsAg)positive]are reasonably all treated.Past/resolved HBV patients(HBsAg negative)are the actual area of uncertainty where it could be difficult choosing between prophylaxis and pre-emptive strategy.
文摘为了构建猪圆环病毒1型(porcine circovirus type 1,PCV1)和猪圆环病毒3型(porcine circovirus type 3,PCV3)的嵌合病毒PCV1-3,并为PCV3疫苗研制奠定基础,该研究以PCV1基因组为骨架,将PCV1的ORF2基因替换为PCV3的ORF2基因,构建嵌合型猪圆环病毒(PCV1-3)DNA克隆。PCR和序列测序结果显示,成功构建出了PCV1-3感染性克隆;将感染性克隆转染PK-15细胞,并将第4代病毒进行免疫过氧化物酶单层试验(IPMA)和蛋白免疫印迹(Western Blot)检测,结果显示成功拯救了重组病毒PCV1-3。对第4代病毒进行滴度测定,效价为105.13 TCID 50/mL。因此,该试验成功拯救出一种新型嵌合型病毒PCV1-3,并为进一步研究PCV3疫苗奠定了基础。
基金Supported by The Key Research Projects of Science and Technology of Sichuan Province,No. 2022YFS0189
文摘Hepatocellular carcinoma(HCC)is associated with high morbidity and mortality,and is prone to intra-and extrahepatic metastasis due to the anatomical and functional characteristics of the liver.Due to the complexity and high relapse rate associated with radical surgery or radiofrequency ablation,immune checkpoint inhibitors(ICIs)are increasingly being used to treat HCC.Several immunotherapeutic agents,along with their combinations,have been clinically approved to treat advanced or recurrent HCC.This review discusses the leading ICIs in practice and those currently undergoing randomized phase 1-3 trials as monotherapy or combination therapy.Furthermore,we summarize the rapidly developing alternative strategies such as chimeric antigen receptor-engineered T cell therapy and tumor vaccines.Combination therapy is a promising potential treatment option.These immunotherapies are also summarized in this review,which provides insights into the advantages,limitations,and novel angles for future research in establishing viable and alternative therapies against HCC.
文摘Green fluorescent protein(GFP)gene was inserted into the pseudogene(ψ)region of genome of rabies virus rHep-Flury strain,and a recombinant rabies virus carrying GFP,designated as HEP-GFP,was rescued by reverse genetics system.It was demonstrated that green fluorescent protein could be expressed in the chimeric virus after 5 passages in BHK-21 cell line.The research indicated that the pseudogene(ψ)region in the genome of rHEP-Flury strain,as an independent functional unit in the process of virus assembly,could independently carry and express exogenous genes.
