Passage number? - (Nov/23/2011 )

When working on non-immortalised cell lines, how do my fellow researchers define a passage?

Example is: I thaw out primary (P0) cells from the liquid nitrogen and seed them down onto culture flasks. Are the cells considered as P0 or P1?

Same thing applies to when I trypsinise e.g. P10 cells from culture to be frozen down. Are they P10 or P11?

science noob on Wed Nov 23 13:17:34 2011 said:

Dear Science noob,


This is what I do:

Primary cells from tissue are isolated and plated ...these are P0
Grown and then trypsinised =P1

Vial from frozen labelled P10.....thawed and plated =P10
Grown and trypsinised =P11

Passage number is vitally important with most cells but especially Primaries. Primary cells can dramatically change just in one passage

For example : Primary Porcine Aortic Endothelial cells (PAEC) will produce Prostaglandin I2 (prostacyclin) at P0 with no detectable Prostaglandin E2
PAEC at P1 will produce Prostaglandin E2 predominately and very little prostacyclin.
Thus in one passage the prostaglandin profile radically changes.


However compare this to a J774.A1 cell (Murine macrophage)......my record is over 200 continuous passages (1 year), no contamination and importantly no difference in enzyme induction profile from one passge to another.

Hope you find this useful

Kindest regards

Uncle Rhombus