RESUMEN
The generation of large quantities of novel human T cell clones ex vivo would make a wide range of gene-and immuno-therapies for tumor and AIDS possibly. Although it is well established that T cells are derived from CD34(+) cells, the involvement of thymic fragments from either human or murine fetus makes the in vitro T cell perliferation very cumbersome. In this report, cord blood mononuclear cells were used as accessory cells to support the differentiation of CD34(+) cells into naive T cells stimulated with SCF and IL-2. CD4(+) and CD8(+) T cells, under the cultural conditions, were continuously produced in vitro at least over a period of 3 weeks and their ratios changed gradually. CD4/CD8 double positive T cells and RAG-2 gene were existed, and RAG-2 gene, reponsible for TCR rearrangement, was expressed during the cell proliferation. Our study presents a simple culture system in vitro to acquire large quantities of naive T cell clones.
RESUMEN
Many gene therapy protocols can induce antitumor immunity, however, the ex vivo approach restricts their uses. This sutydy intended to induce antitumor immunity by direct transfer of MHC class Ⅱ gene in vivo. Methods: MHC class Ⅱ gene cDNA was introduced directly into two tumors: P815, (a murine weak immunogenic mas-tocytoma) and B16 (a murine nonirnmunogenic melanoma) to observe the survival rate of the mice. Results: Tumori-genicity of P815 was reduced when MHC class Ⅱ gene was introduced directly into tumors in vivo. Further more, most vaccinated mice could survive after second challenge of P815. Co-injection of MHC class Ⅱ and B7 genes in the B16 also resulted in the tumor grow slowly, while the injection of MHC class Ⅱ gene was not enough to induce effective antitumor responses. Conclusion: The results showed the potential applications of direct transfer of MHC class Ⅱ gene in the treatment of tumor.