Hi i would like to know the general way of indicating passage number to cells. I have heard that some people label the cell passage number as zero upon receipt from company. while some would just continue off from the passage number indicated on cryovial.
which is the right way of doing it?
Hello
Never, NEVER (!!!) write zero, when you have another passage number. The Passage number is also some kind of "age" for the cells. When you always write passage zero, when you get a new cellline, its like an old woman who tells everybody she´d be 29.
Also freezing is plus 1 passage and thawing is plus 1 passage. so most celllines are evtl older
I agree with Ninon. Further, when you culture cells, the number of population doubling needs to be noted. Traditionally, cells are split 1:4 and two population doubling will result in confluence of cells. Consequently, each passage of cell represents roughly two population doubling. Importantly, when dealing with immortalized cell lines, population the number of doublings or passage number may reflect accumulation of additional mutations in cells and alterations in their phenotype(s).
Hi, write passage number written on the vial and then continue.....because first passage after the primary culture is the passage number 1 which increases with every subculture you are doing. When a company claims a particular passage number of a cell line it means they have frozen it on that passage number.
Hello Iwan,
I agree with the previous comments. If you got a passage number use that one and continue onward. What we usually do is to mark the passages in our lab with a "+" so you know how long you got them and you don't always need to write p22+6 but just "+6". It is very important to keep track of this and also if you freeze down stocks and want to work with them two year later it is important to know which passage you're working with to explain certain phenomena. It also depends on your cell line, if you have a highly malignant, highly instable cancer cell line the results from passage 12 to 66 may be very different due to additional acquired mutations.
Bottom-line: keep track of the passage number, it will make your life much easier.
Good Luck!
I agree with Thomas. I would generate a cell bank for the vendor cell line as early as possible (e.g. 8-10 vials at P1 or P2 post-resuscitation) and then use this as your working bank. I too label them as vendor passage number + my passage number. Always return to this bank when you feel the cells are getting old (e.g. beyond about P30). When this bank is nearly used up, generate another bank (they will now be e.g. P3 or P4 post-resuscitation of the vendor vial). Don't make a bank when they are e.g. P30 or P40!) If you thinkl they might have changed, get them re-fingerprinted.
Make sure you write clearly on the vial what they are and in your LN2 storage log so somebody else can find them in the future and know what they are (it's amazing how many people do not!!)
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