RESUMO
Embryonic hematopoiesis in mammals is characterized by successive temporal and spatial changes. Previous investigations indicate that in vitro differentiation of embryonic stem cells (ES cells) derived from 129 mice can mimic embryonic hematopoiesis to some extent. To investigate the in vitro hematopoietic differentiation capacity of ES cells derived from C57BL/6 mice, the authors initially established the murine ES cell line with standard identification methods employed. Next, two-step culture system was utilized for embryoid bodies formation and the appearance of different hematopoietic precursors was confirmed by CFC assay, cellular chemical staining as well as RT-PCR. The results demonstrated that the ES cell line MES-1 fulfilled the criteria of ES cell line and its progeny after in vitro differentiation included primitive and definitive erythrocyte precursors, mixed colony-forming cells and granulocyte/macrophage colony-forming cells. RT-PCR analysis revealed the molecular consistence of transcription factors and hematopoietic markers with cellular event. In conclusion, MES-1 established from C57BL/6 mice was able to differentiate in vitro to a variety of hematopoietic precursors, thus could partly recapitulate embryonic hematopoiesis.
Assuntos
Animais , Camundongos , Técnicas de Cultura de Células , Métodos , Diferenciação Celular , Genética , Linhagem Celular , Ensaio de Unidades Formadoras de Colônias , Proteínas de Ligação a DNA , Genética , Embrião de Mamíferos , Biologia Celular , Eritroblastos , Biologia Celular , Metabolismo , Células Precursoras Eritroides , Biologia Celular , Metabolismo , Fatores de Ligação de DNA Eritroide Específicos , Expressão Gênica , Células-Tronco Hematopoéticas , Biologia Celular , Metabolismo , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células-Tronco , Biologia Celular , Metabolismo , Fatores de Tempo , Fatores de Transcrição , Genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular , GenéticaRESUMO
CD40/CD40L interactions play a pivotal role in T cell activation, and take part in many physiologic and pathologic procedures and different levels. In this article, stable CHO transformants secreting human CD40-Ig fusion protein were established through transfection and selection with Lipofectamaine and G418, respectively. In order to obtain great valume of recombinant protein, big batch serum-free cultures of engineered CHO cells were performed in roller-bottle using CHO-II-SFM medium. After cultures, the cell-culture supernatants were harvested, concentrated through ultra-filtration, and finally purified by affinity choromatography with Protein G Sepharose Fast Flow. Human peripheral bloods were collected freshly and seperated with Ficoll, CFU-T was cultured in semi-solid culture system with peripheral blood mononuclear cells (PBMNC). Effect of human CD40-Ig fusion protein on the formation of CFU-T was observed in vitro. The results showed that the yield of human CD40-Ig fusion protein was 30 mg in total 3 liter CHO-II-SFM culture supernatant, and it supposed that the expression level of CD40-Ig in CHO cells was more than 10 micro g/ml. The purity of purified fusion protein is above 95%. Furthermore, compared with human IgG, human CD40-Ig fusion protein significantly inhibited the formation of CFU-T at dose 0.25, 1.0, 4.0, and 10 micro g/ml, it lays a good foundation to evaluate its potential functions in vivo.