Objective To establish a high-performance induction culture system for Raw264.7 cells to differentiate into osteoclasts(OC)invitro by improving the cell culture program.Methods The Raw264.7 cells were cultured withα-MEM medium containing 50 μg · L-1 M-CSF, 100 μg · L-1 RANKL, and 1 × 10-8 mol · L-1 1α,25-(OH)2 D3 in 5% CO2 for 12 d at 37℃. The cells were digested transiently every time before the medium was changed after every three days. The morphologic changes of the Raw264.7 cells were observed by inverted microscope.The maturation and phagotrophic function of OC were identified by HE,TRAP,FITC-phalloidin staining and immunofluorescence.Results The cells remained to grow in single layers all the time in most areas of the well during the whole induction by the improved culture program. The observation results of inverted microscope and HE staining showed that the growth area of the polykaryotic OC reached to 70% of the well on day 1 2. FITC-phalloidin staining showed that in the maturation of the OC, the cluster-shaped podosomes in the pseudopodia gradually transformed into rings,which finally fused to form a large belt surrounding the periphery of the cytoplasm. The calcitionin receptor (CTR) expressed by OC was markedly enhanced compared with the precursor cells by immunofluroescence staining,and a large number of red granules appeared in the cytoplasm of OC with TRAP staining on day 1 2. These results comfirmed that the obtained OC were maturated and owned phagotrophic function. Conclusion A high-performance induction culture system for Raw264. 7 cells to differentiate into OC in vitro induced by combination of 50μg · L-1 M-CSF, 100 μg · L-1 RANKL,and 1 × 10-8 mol·L-1 1α,25-(OH)2 D3 is established by improving the cell culture program.

Unnatural amino acid orthogonal translation machinery can insert unnatural amino acids at desired sites of protein through stop codon by means of foreign orthogonal translation system composed of aminoacyl-tRNA synthetase and orthogonal tRNA genes. This new genetic engineering technology is not only a new tool for biochemical researches of proteins, but also an epoch-making technology for the development of new-type live viral vaccines. The mutated virus containing premature termination codon in genes necessary for replication can be propagated in transgenic cells harboring unnatural amino acid orthogonal translation machinery in media with corresponding unnatural amino acid, but it cannot replicate in conventional host cells. This replication-deficient virus is a new-type of live viral vaccine that possesses advantages of high efficacy of traditional attenuated vaccine and high safety of killed vaccine. This article reviews the application and prospect of unnatural amino acid orthogonal translation machinery in the development of novel replication-deficient virus vaccines.
Amino Acids ; genetics ; Amino Acyl-tRNA Synthetases ; Genetic Engineering ; Protein Engineering ; RNA, Transfer ; Viral Vaccines