My understanding of cryopreservation and cell marker staining (CD40, CD34,&c) is that the cells must be stained prior to freezing; otherwise, many or most of the surface molecules are lost and their binding abilities are compromised. I guess this depends upon what you are looking at, but I think it is best to stain the cells first and then freeze them. Also, the comparison between samples stained simultaneously is more accurate than that between samples stained at different times simply because small technical variations (in the quantity of staining reagent used, incubation time, temperature, &c) can lead to fairly significant differences in how the cells take up the stain. Hope this helps. ___________________________ Tyler F. Creelan OSU Dept. Microbiology Nash 552 737-5094 On Tue, 8 Aug 2000, Liza McGuire wrote: > Good-day to you flowers, > > I am searching for guidelines and/or standards that involve testing peripheral blood stem cell collections post cryopreservation. At this point our laboratory is testing for viability, sterility, CD34 enumeration and CFU at the point of collection (fresh sample) as well as at the point of infusion (post thaw). Is it necessary to do all of the testing post cryopreservation? Naturally, the results will not correlate with pre cryopreservation. Furthermore, they are time consuming and the decision for the stem cell infusion dose has already been made. I would consider any post cryopreservation data points to be useful for future clinical research studies. What do you think? > I have checked into FAHCT guidelines and if I understood correctly the decision is left up to the laboratory director. > I am trying to get a feel of what the "norm" might be. What is the consensus? I appreciate and I will be grateful for any input that you may have. > Thanks a bunch in advance, > Liza McGuire > Bone Marrow Processing Lab > Thomas Jefferson University Hospital > 130 S 9th Street, Rm. 400 Edison > Philadelphia, PA 19107-5233 > (215)955-9646 > >
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