Objective: To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion. Methods:Gene fragments were obtained using PCR...Objective: To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion. Methods:Gene fragments were obtained using PCR technique and eukaryotic expression vector(containing immunostimulatory sequence) was built. BALB/c mice were divided into PBS control group, empty vector control group and study group and were immunized at week 0, 3 and 6 respectively. Blood was collected 2 weeks after each immunization and serum was separated to detect the Ig G, Ig G1 and Ig G2 a levels. Spleen of mice was obtained for preparation of splenic mononuclear cell and the cytokine IL-4 and IFN-αlevels were detected. Indirect immunofluorescence and western blot were employed to verify the specificity of antiserum. Sporozoite and merozoite invasion were used respectively to detect the immune protective effect 2 weeks after the third immunization. Ookinete conversion rate in vitro and oocyst numbers of mosquito stomach were observed to evaluate the transmission-blocking levels. Results: In GAMA DNA vaccine group: antiserum could be combined with recombinant protein specifically and green fluorescence signals of merozoite, ookinete and sporozoite were observable, while specific fragments and fluorescence signals were not observable in empty vector group. Compared with control group, specific Ig G in DNA vaccine immunity group significantly increased(P<0.01), and Ig G1 and Ig G2 a all increased(P<0.01). IL-4, IFN-αcontent in study group significantly increased, compared with control group(P<0.01). GAMA DNA vaccine immunity could not obviously block the erythrocyte-stage infection(caused by sporozoite invasion); compared with control group, liver worm load was slightly reduced(P<0.05), and antiserum ookinete numbers(cultured in vitro) had no significant difference with oocyst numbers of mosquito stomach in DNA vaccine group. Conclusions:GAMA has good antigenicity, which could stimulate the body to produce specific immune responses; while DNA vaccine immunity could not play a good protective effect, the effect of which is only limited to the slight reduction of liver worm load, and has no obvious erythrocytestage protective effect and transmission-blocking effect. Therefore, trying other immunization strategies for further research on the value of GAMA(as multi-stage antigen vaccine and multistage combined vaccine components of the life-cycle of plasmodium) is necessary.展开更多
Vasco da Gama＇s voyage around the Cape of Good Hope to East Africaand further arrival in India in 1498 is considered as a great event inhistory. Yet contact between China and Africa started as early as in theHan Dyna...Vasco da Gama＇s voyage around the Cape of Good Hope to East Africaand further arrival in India in 1498 is considered as a great event inhistory. Yet contact between China and Africa started as early as in theHan Dynasty （206 B. C.- A. D. 220）. Du Huan of the Tang Dynasty （618-907） left a note about his visit to Africa in the 8th century. Porcelains fromTang to the Ming Dynasty （1368-1644） were found in Africa. Ibn Battutavisited China in the Yuan Dynasty （1271-1368）. There is a Chinese silkmap of Africa in the 14th century. Zheng He＇s junk visited Africa in theearly 15th century. This paper is intended to examine the archeologicalevidence, related documents and historiography in Chinese on earlyChina-Africa contact thus to probe the early bilateral relations. It willdivide into four parts, the study of the period of the pre-Tang Period,Tang Dynasty, Song （960-1279） and Yuan dynasties, and finally earlyMing Dynasty, respectively. It demonstrates that China-Africa contactprobably started before the birth of Jesus Christ, Africans came to Chinain ancient times through different ways, and Chinese had sailed to Africalong before Vasco da Gama.展开更多
基金supported by National Natural Science Foundation of China(NSFC)(No.81471978)
文摘Objective: To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion. Methods:Gene fragments were obtained using PCR technique and eukaryotic expression vector(containing immunostimulatory sequence) was built. BALB/c mice were divided into PBS control group, empty vector control group and study group and were immunized at week 0, 3 and 6 respectively. Blood was collected 2 weeks after each immunization and serum was separated to detect the Ig G, Ig G1 and Ig G2 a levels. Spleen of mice was obtained for preparation of splenic mononuclear cell and the cytokine IL-4 and IFN-αlevels were detected. Indirect immunofluorescence and western blot were employed to verify the specificity of antiserum. Sporozoite and merozoite invasion were used respectively to detect the immune protective effect 2 weeks after the third immunization. Ookinete conversion rate in vitro and oocyst numbers of mosquito stomach were observed to evaluate the transmission-blocking levels. Results: In GAMA DNA vaccine group: antiserum could be combined with recombinant protein specifically and green fluorescence signals of merozoite, ookinete and sporozoite were observable, while specific fragments and fluorescence signals were not observable in empty vector group. Compared with control group, specific Ig G in DNA vaccine immunity group significantly increased(P<0.01), and Ig G1 and Ig G2 a all increased(P<0.01). IL-4, IFN-αcontent in study group significantly increased, compared with control group(P<0.01). GAMA DNA vaccine immunity could not obviously block the erythrocyte-stage infection(caused by sporozoite invasion); compared with control group, liver worm load was slightly reduced(P<0.05), and antiserum ookinete numbers(cultured in vitro) had no significant difference with oocyst numbers of mosquito stomach in DNA vaccine group. Conclusions:GAMA has good antigenicity, which could stimulate the body to produce specific immune responses; while DNA vaccine immunity could not play a good protective effect, the effect of which is only limited to the slight reduction of liver worm load, and has no obvious erythrocytestage protective effect and transmission-blocking effect. Therefore, trying other immunization strategies for further research on the value of GAMA(as multi-stage antigen vaccine and multistage combined vaccine components of the life-cycle of plasmodium) is necessary.
文摘Vasco da Gama＇s voyage around the Cape of Good Hope to East Africaand further arrival in India in 1498 is considered as a great event inhistory. Yet contact between China and Africa started as early as in theHan Dynasty （206 B. C.- A. D. 220）. Du Huan of the Tang Dynasty （618-907） left a note about his visit to Africa in the 8th century. Porcelains fromTang to the Ming Dynasty （1368-1644） were found in Africa. Ibn Battutavisited China in the Yuan Dynasty （1271-1368）. There is a Chinese silkmap of Africa in the 14th century. Zheng He＇s junk visited Africa in theearly 15th century. This paper is intended to examine the archeologicalevidence, related documents and historiography in Chinese on earlyChina-Africa contact thus to probe the early bilateral relations. It willdivide into four parts, the study of the period of the pre-Tang Period,Tang Dynasty, Song （960-1279） and Yuan dynasties, and finally earlyMing Dynasty, respectively. It demonstrates that China-Africa contactprobably started before the birth of Jesus Christ, Africans came to Chinain ancient times through different ways, and Chinese had sailed to Africalong before Vasco da Gama.
