We experience from time to time that in cultured wild boar lung cells foci appear 1-2 days after propagation in which cells are apparently dead (circle in left picture). One day later, nearly the entire culture is affected (right picture). Trypsinization of these cells results in normal cell cultures in which this effect may sometimes appear for one or two further passages but then the effect disappears. Although the cells appear infected, virus or bacteria are not involved.Transfer of affected cells to nonaffected cells does not lead to spread. In the lab we call this effct Lemming effect because we feel that individual cells are triggered to die and then ask their neighbours to join them. Would be very happy if someone could explain what happens and may perhaps have a solution.
Best,
Günther
Dear Dr. Did you make a sterility test? it is preferable that the test lasts seven days to be sure that there isn’t any source of contamination
In linfoblastoid cells lines (LCL) may occurs this "lemming effect" if cell are not at proper density (normally at lowers densities) . When infected cells with EBV are in the same dish with other that are not transformed, they came like fibroblast , greater, larger,..., and is difficult to stop this "paracrine effect": some substances secreted around your "lemmings cells" make that some cells do the same.
My experience with LCL´s tells me that just stop sometimes, changing the culture médium or even the culture plate to remove those factors that cause abnormal growth or death
Hi Günther,
I found the same phenotype with DF-1 cells, immortalized avian fibroblasts, but in an other context. This cell type is rather difficult to propagate after freezing-defreezing cycle. After defreezing, the cell culture rapidly reaches confluency but a very small proportion of "apoptotic" cells can trigger a similar effect as you describe with your wild board lung cells. The only solution we found is a frequent and rapid medium replacement after defreezing and this must be done several times during the first passages after defreezing. To identify the molecules, proteins involved in the signaling, a comparative proteomic approach might be used , but is it feasible ? With my best regards,
Benoît
I would agree with Benoit that cell death within a crowded region is likely to spread. However it might not be apoptosis. There are several factors that may make the cells more susceptible to either apoptosis or necrosis . The most likely would be a) the presence of mycoplasma, simply check for that, b) depletion of a key ingredient. Glutamine is a common culprit but there may be something more specific related to these particular cells.
Your story is very similar to bystander effect that is well known in radiobiology. In our studies this effect was mediated by hylrogen peroxide (Pletjushkina OY, et al. Long-distance apoptotic killing of cells is mediated by hydrogen peroxide in a mitochondrial ROS-dependent fashion. Cell Death Differ. 2005 Nov;12(11):1442-4.)
There is an easy test. Just add catalase to the medium.
Good luck.
- Badges
- Science topic
- Similar topics
- Biological Science
- Cell Biology
- Culture Cells