We have previously produced transgenic (TG) mice expressing the human lactoferrin (hLF), interleukin-10 (hIL-10), and thrombopoietin (hTPO) proteins in the milk. In this study, we examined whether simple crossbreeding between two kids of a single transgenic mouse can produce double transgenics co-expressing two human proteins.. The hLF male, and the hIL-10 male were crossbred with the hIL-10 and hTPO females, and the hTPO female, respectively. PCR analysis for genotyping showed 32%, 23% and 24% double transgenic rates for hLF/hIL-10, hLF/hTPO, and hIL-10/hTPO transgenes, respectively. We analyzed the expression levels of the human proteins from double transgenic mice and compared those with their single transgenic siblings. All double transgenic co-expressed two human proteins at comparable levels to singles', unless hTPO was not co-expressed: for hLF, 1.1 mg/ml in hLF/hIL-10, whereas 0.5 mg/ml in hLF/hTPO; for hIL-10, 4.1 mg/ml in hIL-10/hLF, whereas 1.4 mg/ml in hIL-10/hTPO. Ihe downregulation of hTPO to half level of singles' was observed in double transgenic mice. The possible reason why hTPO co-expressed might lead to down-regulation of another human protein was discussed. These results suggested that double transgenic generated by crossbreeding between two singles' could be useful system for bioreactor.

Cytokines play a vital role in the host immune response by regulating the development and function of im munocompetent ce11s One immunomodulatory agent that has received attention in oncology research recently is interleukin - lO(IL-lO). IL-IO inhibi ted tumor antigen presenta tion and induced energy in T lymphocytes that had been s timu lated by autologous MHC class II positive tumor ce11s Patients with head and neck cancer have been shown to exhibit profound irnmunosuppression. The mechani sm by which tumor ce11s alter immunological function in the host is poorly understood. Recently. production of biological active IL- IO was confirmed in ovar‘ian cancer, melanoma, skin cancel‘ & head and neck cancer, suggesting that IL- lO reduces the function of tumor infiltrating lymphocytes and contributes to the tumor growth. IL-IO expression has not been examined extensively in human oral cancer and has not yet been cla rified. The purpose of t his study were to investigate IL-IO mRNA and protein expression in NHOK, IHOK and oral squamous ce11 carcinoma(OSCC) ce11 line by RT-PCR and irnmunoslot blotting, and to apply its results to examine its thera peutic significance for oraJ cancers. Cultured NHOK showed a lower level of IL-IO mRNA and protein expression than cultured IHOK and HN 22 OSCC cell line under pre and postconfluency. HN 22 OSCC cell line under pre and postconfl u ency. showed the highest level of IL-I0 Cul tured IHOK showing a intermediate expression of IL- IO could be as a vaJ u a bJe marker for oral carci nogenesis ste p. During the terminal differentiation of a11 the ce11 lines, IL- IO ex pression was significantly unchangeabl e. IL- IO mRNA expression of a11 the ce11 lines was consistent with IL-10 protein expression. It suggested that IL- lO expression might play an important role in oral carcinogenesis and IHOK could be a valuable marker for oral carcinogenesis step. And aJso IL- 10 related gene may be future targets for gene discovery and possi bJy therapeutic intervention