Black Debris in T-Cells - debris in my cell culture (Jun/26/2005 )

Hi
I hope someone can help me. I have black specks in my T-Cell cell cultures. Some of the plates and cell lines have more of it then cells other cell lines do not seem to be affected by it. I have looked at it under the scope and fluoresce and it doesn't seem to move or look like any thing but a clump of protein. I have tried plating it on an agar plate and in tubes and it doesn't grow. One of my friends thought it looked like plant type debris. I did find some black specks in a media boat and it looked similar under the scope but how did it get there. Those boats are sterile in there tiny bags. Has anyone seen these specks? One chick I work with said she saw them before and that they do no harm and they called them pepper where she worked before.
We have changed serum do you think it could be from that. But it isn’t in all my cultures. It looks like some kind of percipate. Maybe?

Please help me. I am supposed to be an expert and I have never seen anything like this in 15 years of cell culture.

Janet

Hi Janet,

From your description, it looks like you are looking at exosomes, lipid encased particles spewed out by several cell types, including T cells. Cancer cells, Dendritic cells and B cells burp out exosomes which contain MHC-antigen complexes. Exosomes secreted out by T cells have not been studied much. It's also not clear what conditions trigger excessive secretion of exosomes by cells.

Please let me know if you find out something more about your black specks

Take care !

Para.

Hello Janet & Para,

A couple months ago, working in my cultures (endometrial cancer cell line), I noticed this black precipitate at the bottom of some culture flasks, similar to Janet's description. Obviously, we performed all basic procedures to detect bacterial/fungal contamination. But misteriously the black specks suddenly dissapeard in the cultures, so we decided not to continue investigating what it was. Para's contribution would finally give me an answer. Thank you both.

Hi Janet,

I have found some black adherent dots in my Human Aortic endothelial cells after retroviral transduction. They seem to attach to the plate and are not affecting cell morphology and growth so far. Could you please help me in this regard if you have information on what these particles could be. I have control Human endothelial cells that are not infected with retrovirus in the same incubator and they look fine.

Thanks so much,
Anita.

Hi
I hope someone can help me. I have black specks in my T-Cell cell cultures. Some of the plates and cell lines have more of it then cells other cell lines do not seem to be affected by it. I have looked at it under the scope and fluoresce and it doesn't seem to move or look like any thing but a clump of protein. I have tried plating it on an agar plate and in tubes and it doesn't grow. One of my friends thought it looked like plant type debris. I did find some black specks in a media boat and it looked similar under the scope but how did it get there. Those boats are sterile in there tiny bags. Has anyone seen these specks? One chick I work with said she saw them before and that they do no harm and they called them pepper where she worked before.
We have changed serum do you think it could be from that. But it isn’t in all my cultures. It looks like some kind of percipate. Maybe?

Please help me. I am supposed to be an expert and I have never seen anything like this in 15 years of cell culture.

Janet