dear sara,

you have different problems, first use absolutely PBS with Ca2+/mg2+ to stabilize your cytokines. Then, be careful, BSA from Sigma Aldrich (A-4503) that you used has an acidic pH (5), you may destroy lake that your protein. it's better if you use neutral BSA, with high purified ratio. Depending of your subject, try to use also endotoxin free BSA. According to my experience, you can reconstitute your cytokine in PBS with Ca2+/Mg2+ plus BSA 0.1% (neutral ph, ultra pure) and store during a long time at -80°C at this concentration (1.000 ng/ml). however, do not forget that avoid refreeze aliquot nor a long time 4°C exposure (no more one week). let me know

which sort of PBS, you should only use PBS containing Ca2+/Mg2+ to reconstitute cytokines or recombinant proteins. purchase from ? i used 20microliter of ultrapure BSA for 1ml of PBS containing cytokines. let me know.

I use the Lonza BioWhittaker PBS (BE17-516F), without Ca2+/Mg2, and albumin from bovine serum (lyophilized powder) from Sigma Aldrich (A-4503), to reconstitute IL-6 at a concentration of 1.000 ng/ml. In the product insert I didn't find any information about buffer's special requirements. Thanks a lot for your help!

dear sara,

you have different problems, first use absolutely PBS with Ca2+/mg2+ to stabilize your cytokines. Then, be careful, BSA from Sigma Aldrich (A-4503) that you used has an acidic pH (5), you may destroy lake that your protein. it's better if you use neutral BSA, with high purified ratio. Depending of your subject, try to use also endotoxin free BSA. According to my experience, you can reconstitute your cytokine in PBS with Ca2+/Mg2+ plus BSA 0.1% (neutral ph, ultra pure) and store during a long time at -80°C at this concentration (1.000 ng/ml). however, do not forget that avoid refreeze aliquot nor a long time 4°C exposure (no more one week). let me know

Hi Lepelletier Yves,

Is it possible to use FBS instead of BSA? i use hIL-6 from "Cell Signaling" (#8904LC)