cytokine stability in whole blood

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PMartinez
PMartinez's picture
cytokine stability in whole blood

hello,

I'm wondering if whole blood samples kept at 1-6 C for 24 hours immediately after draw and then separated into serum and plasma and stored at -80 C for X amount of time would still be appropriate for ELISA testing for cytokines. I understand the half-life of cytokines to be about 60 minutes but wonder if reduced temperature, even in whole blood, would suffice to maintain a similar cytokine level as to what existed originally. 

Thanks for the help. 

Priscilla

heehawmcduff
heehawmcduff's picture
Hey,

Hey,

While not having a definitive answer for you, I do have a couple of comments

First, when looking at the data sheets for recombinant cytokines (such as TNF or IL-8), companies suggest that when lyophilised samples are reconstituted, some can be stored for 5-7 days at 4 degrees without major loss of activity.  The caveat to this is that these samples are reconstituted in a sterile salt solution which would not contain any of the proteases etc found in blood samples.  So I would guess that the stability of cytokines in biological fluids is a lot less than in sterile PBS solutions and you would therefore see a more rapid degradation/loss of activity in your blood sample.

Secondly, a good way to test this would be to add a recombinant cytokine to a whole blood sample and run an ELISA for it immediately and after 24 hours and compare them to a cytokine sample that hasn't been exposed to blood.  I guess that would give some idea of the amount of degradation that would take place.

If you find out, please post.

 

PMartinez
PMartinez's picture
Hey,

Hey,

Thanks for the prompt reply.

I agree with your first comment that the stability of cytokines in biological fluids is quite low and easily compromised, especially given the presence of soluble receptors and cell re-uptake. Although its good to know some lyophilised samples can be reconstituted and stored for days at just 4 degrees.

I would love to carry out your suggested experiment, and may very well do so in the future on our "leftover" samples (if they let me loose in the lab, its been awhile). 

I'm still looking in various places to find out if close to freezing temperature notably maintains cytokine stability in whole blood and serum samples and will post an answer if I find one.

mkhare2009
mkhare2009's picture
HI

HI

I saw your post here about cytokines and I am also dealing with same problems. Did you find out about how long cytokine stay stable at RT or at 4oC. Because I am doing cytokine assay using bioplex assay, and having trouble getting enough numbers.
I have to get serum from various clinics arround US and most of the samples arrive ON but in RT.  When I do inhouse test that is getting serum here in lab from volunteers, I found that the value disintegrtates very fast with in few hour for TNF a , IL12. but some becomes more in amount.
Can you tell me your predictions..........

thanks

newscientist2010
newscientist2010's picture
 Hi

 Hi

Try getting the samples transported in dry ice. When they come, immediately make single-use aliquots and dump it in -80. You can go to sleep even for 6 months, come back, do a bioplex and still get good enough numbers. Avoid freeze-thaw cycles at any costs.

Good luck!!!