I am using CD3/CD28 beads (gibco) for activating CD8 T cells (1:1 ratio). The T cells are isolated via a CD8 isolation Miltenyi column from freshly collected PBMCs. In 4 different donors I have seen a dramatic decrease in the cell counts (and viability to a lesser extent) after 2 days of activation. As I need a high cell viability for knocking out the cells downstream this is causing me a big time problem.
I am wondering what is causing loosing the count and viability of the CD8 cells after activation. Has it ever happened to you?
Hi, Dr. Rayzan.
Maybe you did not check the importance of IL-2 for activating CD8 T cell with CD3/CD28 beads.
If CD3/CD28 co-stimulation occurs without IL-2, it would likely result in a suboptimal or incomplete T cell response. While CD3/CD28 signaling can provide the initial activation signal, IL-2 is required for sustained proliferation and survival of T cells.
This is a reference.
https://www.isct-cytotherapy.org/article/S1465-3249(05)70828-8/fulltext
According to this article, exogenous IL-2 is needed for maintaining T cell function and survival after transfer.
Additionally, if the naive T cells encounter APCs displaying parts of antigen using MHC molecules, the cells will be activated and secrete IL-2. However, you already purified CD8+ T cells from PBMCs, so there are no mechanistic actions for secreting IL-2 by themselves. Because of this reason, exogenous IL-2 will be needed for your work.
I hope your problem gets resolved as soon as possible!
Thank you.
Junhyung.
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