A single immunization with HA DNA vaccine by electroporation induces early protection against H5N1 avian influenza virus challenge in mice

<p>Abstract</p> <p>Background</p> <p>Developing vaccines for the prevention of human infection by H5N1 influenza viruses is an urgent task. DNA vaccines are a novel alternative to conventional vaccines and should contribute to the prophylaxis of emerging H5N1 virus. In this study, we assessed whether a single immunization with plasmid DNA expressing H5N1 hemagglutinin (HA) could provide early protection against lethal challenge in a mouse model.</p> <p>Methods</p> <p>Mice were immunized once with HA DNA at 3, 5, 7 days before a lethal challenge. The survival rate, virus titer in the lungs and change of body weight were assayed to evaluate the protective abilities of the vaccine. To test the humoral immune response induced by HA DNA, serum samples were collected through the eye canthus of mice on various days after immunization and examined for specific antibodies by ELISA and an HI assay. Splenocytes were isolated after the immunization to determine the antigen-specific T-cell response by the ELISPOT assay.</p> <p>Results</p> <p>Challenge experiments revealed that a single immunization of H5N1 virus HA DNA is effective in early protection against lethal homologous virus. Immunological analysis showed that an antigen-specific antibody and T-cell response could be elicited in mice shortly after the immunization. The protective abilities were correlated with the amount of injected DNA and the length of time after vaccination.</p> <p>Conclusion</p> <p>A single immunization of 100 μg H5 HA DNA vaccine combined with electroporation was able to provide early protection in mice against homologous virus infection.</p

Social-capital mobilization and income returns to entrepreneurship: the case of return migration in rural China

Temporary labor migration in developing countries is an important urban - rural linkage that has a potential impact on rural development. According to the new economies of labor migration, it is often a strategy used by families with small farms to acquire investment capital for future business formation. In this paper, I argue further that human-capital accretion during migration reinforces the mobilization of local social capital, which in turn enhances a returnee's entrepreneurship. By using the results of an in-depth survey of returned labor migrants in rural China, I seek to explain the mobilization of social capital and income return to entrepreneurship in a multivariate framework. I find that skilled returnees are indeed more prone to mobilize social capital. The income return to local social capital is as considerable as that to investment capital and skills acquired at the urban destination. The findings suggest that the consequences of labor migration can be better understood through the integration of the new economics of labor migration and social capital theories.

Urban labour-force experience as a determinant of rural occupation change: evidence from recent urban - rural return migration in China

An integrated approach to temporary migration in develoing countries is proposed by linking past urban labour-force experience to postreturn entrepreneurial activities. The central argument is that labour migration is a family strategy to acquire both physical and human capital for a future technological transformation. On the basis of an in-depth survey of returned migrants that was conducted in rural China, I focus on the explanation of return rural occupation change in a multivariate framework. I find that it is the improvement of the migrant's skills and entrepreneurial ability rather than their savings and remittances that strongly facilitates a return rural occupational change. The policy implication of the finding is to shift efforts from narrowing intersectoral wage differentials to improving rural learning and training opportunities.

Examining Cross-border Marriages in Hong Kong Since Its Return to China in 1997

With increasing economic integration and social interactions between Hong Kong and Mainland China, cross-border marriages between the two have increased substantially, while the sex ratio of the 25-44 age group has decreased to less than one. The influx of Mainland brides, together with ever-increasing unmarried women in Hong Kong, have put increased pressure on its social and welfare services, and reducing barriers for Hong Kong men seeking Hong Kong women has a significant bearing on social policies. Based on a theoretical perspective that combines assortative mating and societal disparity, the current study examined cross-border marriages in Hong Kong between 1998 and 2005. It was found that Hong Kong grooms with Mainland brides were less likely than Hong Kong grooms with Hong Kong brides to be assortative in terms of education, occupation and natal community. It was also found that Hong Kong grooms often married much younger brides due to their own delayed marriages and second plus marriages. Copyright (c) 2008 John Wiley & Sons, Ltd