久久精品99国产I国产精品国产亚洲精品看不卡I日韩区视频I国产丝袜在线I久久精品小视频Iadn—256中文在线观看I夜夜高潮夜夜爽国产伦精品I亚洲女裸体

These cells represent cells obtained from the microenvironment of the liver that support purified mouse and human CD34+CD38- hematopoietic stem/progenitor cells. Delta-like (Dlk1) /preadipocyte factor-1 (pref-1) is preferentially expressed in AFT024 cells and functions as a positive stem cell regulator.  Due to the presence of the temperature sensitive SV40 T antigen, the AFT024 cells must be grown at 33°C. At 33°C, T antigen binds anti-oncogenes and allows cell division. At higher temperatures, such as 37°C, T antigen is inactivated and the cells can no longer divide. 

Volumes used in this protocol are for 75 cm² flask; proportionally reduce or increase amount of dissociation medium for culture vessels of other sizes.

1.  Remove and discard culture medium.
2. Briefly rinse the cell layer with 1X PBS (Ca⁺²/Mg⁺²-free, ATCC SCRR-2201) to remove all traces of serum that contains trypsin inhibitor. 
3. Add 2.0 to 3.0 mL of 0.25% (w/v) Trypsin / 0.53 mM EDTA solution to flask and observe cells under an inverted microscope until cell layer is dispersed (usually within 5 to 15 minutes).

Note: To avoid clumping do not agitate the cells by hitting or shaking the flask while waiting for the cells to detach.  Cells that are difficult to detach may be placed at 33°C to facilitate dispersal.

4. Add 6.0 to 8.0 mL of complete growth medium and aspirate cells by gently pipetting. 
5. Add appropriate aliquots of cell suspension to new culture vessels.

Subcultivation ratio: 1:4 –1:8

6. Place culture vessels in incubators at 33°C.

Note: For more information on enzymatic dissociation and subculturing of cell lines consult Chapter 10 in Culture of Animal Cells, a manual of Basic Technique by R. Ian Freshney, 3rd edition, published by Alan R. Liss, N.Y., 1994.  

Medium Renewal

Two to three times weekly

Moore KA, et al. Hematopoietic activity of a stromal cell transmembrane protein containing epidermal growth factor-like repeat motifs. Proc. Natl. Acad. Sci. USA 94: 4011-4016, 1997. PubMed: 9108096

Miller JS, et al. Single adult human CD34(+)/Lin-/CD38(-) progenitors give rise to natural killer cells, B-lineage cells, dendritic cells, and myeloid cells. Blood 93: 96-106, 1999. PubMed: 9864151

Moore KA, et al. In vitro maintenance of highly purified, transplantable hematopoietic stem cells. Blood 89: 4337-4347, 1997. PubMed: 9192756

Hachney JA, et al. A molecular profile of a hematopoietic stem cell niche. Proc. Natl. Acad. Sci. USA 99: 13061-13066, 2002. PubMed: 12226475

Punzel M, et al. The myeloid-lymphoid initiating cell (ML-IC) assay assesses the fate of multipotent human progenitors in vitro. Blood 93: 3750-3756, 1999. PubMed: 10339481

Thiemann FT, et al. The murine stromal cell line AFT024 acts specifically on human CD34+CD38- progenitors to maintain primitive function and immunophenotype in vitro. Exp. Hematol. 26: 612-619, 1998. PubMed: 9657136

Lewis ID, et al. Umbilical cord blood cells capable of engrafting in primary, secondary, and tertiary xenogeneic hosts are preserved after ex vivo culture in a noncontact system. Blood 97: 3441-3449, 2001. PubMed: 11369635

Fleming, D.O., Richardson, J. H., Tulis, J.J. and Vesley, D., (1995) Laboratory Safety: Principles and Practice. Second edition, ASM press, Washington, DC.

Caputo JL. Biosafety procedures in cell culture. J. Tissue Culture Methods 11:223-227, 1988

Hay RJ, Caputo JL, Macy, ML, Eds. (1992) ATCC Quality Control Methods for Cell Lines. 2nd edition, Published by ATCC.