利用转基因马铃薯生产猪细小病毒病疫苗

将猪细小病毒（PPV）的结构蛋白（VP2）基因通过杆菌转入马铃薯，得到转基因马铃薯再生植株。通过动物试验，以证明其免疫特性。利用转基因马铃薯生产猪细小病毒疫苗，开辟高效、低成本和使用方便的高科技端苗的新途径，克服传统疫苗生产的不足，同时为利用转基因植物生产预防人类及其它动物疾病的疫苗提供理论和实践的依据与参考。

Porcine parvovirus (PPV) is widespread among swine in China. PPV infection does not show clinical disease in the dam. However, infection of pregnant gilts and sows with PPV causes reproductive failure characterized by embryonic and fetal death. The commercially available vaccines, either inactivated or attenuated, is unable to fully protect the dam at present. With the development of molecular biology and the knowing of the gene structure and the code protein of PPV, it is possible to produce a new style vaccine to prevent the PPV infection. Recently, transgenic plants have been investigated as an alternative means to produce and deliver vaccine. There are several reports demonstrating that antigens derived from various pathogens can be synthesized at high level and in their authentic forms in plants. When administered orally, by feeding, such antigens can induce an immune response, and result in immune protection against a subsequent challenge with the pathogen. On the basis of theses background, we caught out the research in the study. Here, the expression vector for the VP2 cDNA of porcine parvovirus was constructed. It was introduced into Agrobacterium tumefaciens strain LAB4404 by direct transformation. Using the modified leaf-disc co-cultivated method, the VP2 gene was transformed into potato (Solanum tuberosum). Potato tuber pieces started to form shoots on shoot-inducing medium containing kanamycin after infected by A.tumefaciens. Regenerated potato tubers were obtained on sucrose enriched medium. PCR and Southern blot analyses showed that the PPV VP2 gene has been integrated into genome of potato. Western blot analyses indicated that the VP2 gene was transcripted and expressed in transgenic plants. To evaluate immunogenicity upon oral administration, the homogenate potato tuber was fed by mice through intragastric intubation. Na?ve and primed mice were intubated intragastrically with 0.5ml homogenate. The na?ve mice did not induce detectable anti-PPV VP2 antibody titeres while the primed animals result in significant anti-PPV antibody response in serum. These results indicate clearly that functional PPV VP2 protein can be produced in potato tubers, that this recombinant protein is immunogenic and that oral administration thereof elicits systemic responses in parentally primed, but not na?ve, animals. The administration of edible vaccine in primed instead of na?ve subjects reveals a more sensitive test system and higher probability of success. Further research is required to optimize this approach and to identify the underlying mechanisms.