cd3- and cd8+ cells - flow cytometry cell population question (Apr/23/2007 )

Hi. I have flow cytometry results in which my cells are negative for CD-3 and positive for CD8. This confuses me, because if a lymphocyte is cd3 negative, then it should be a B cell, but if it is CD8 positive it should be a cytotoxic T cell, right? I've read some literature suggesting that these cells could be Natural Killer cells, but I'm not convinced. I also thought they could be really immature cells. Does anyone have any thoughts on this? I sure would appreciate some help!

Thanks!

-knspartan-

Hello,

Do you have a positive control for your CD3 antibody to make sure it works?

Did you check them for CD4? If they are CD4+CD8+ cells, perhaps they are immature thymocytes with low expression of the TCR complex, although I always thought CD3 was expressed constitutively at all committed T cell stages.

-Cara-

Thanks for replying Cara,

I didn't actually run the test, it was a data set given to me for a class. I thought it might be immature thymocytes, but I wanted a second opinion. Thanks for your help!

QUOTE (Cara @ Apr 23 2007, 04:37 PM)

-knspartan-

QUOTE (knspartan @ Apr 23 2007, 12:14 PM)

If they are CD3- and CD8a+ then they may be DCs as a subset of DCs do express CD8, though usually at a lower intensity than T cells.

-dfitzge-

QUOTE (knspartan @ Apr 23 2007, 06:14 PM)

They are definetly NK cells. In the PBL you usually find something between 2 and 6% of NK cells.
NK cells are CD8+ and CD3-

regards
adri

-Adri-