Ron Lirette <liretter at sial.com> wrote:
>> I am interested in opinions on who's the best in cytokine ELISAs.
> Obviously, there are a number of suppliers, so a choice is tough for a
> non-expert. R&D Systems? Sigma? Genzyme? Who else? Thanks....
Take care. Commercial cytokine ELISA, and other immuno assays, are
are a minefield. Perhaps the following points will assist....
Define the purpose of your assay (ie clinical prognosis, cytokine
production in tissue culture). Some assays are recommended by the
WHO and/or FDA for clinical evaluation and some not.
Check on the inter-assay and intra-assay variation.
Ensure minimal cross-reactivity.
What is the range?
Are there likely to be interfering substances in your sample? For
example cytokine receptors, alpha-2-macroglobulin etc. The importance
of this will be determined by whether or not you wish to assay free of
total cytokine. With regard to a2M, despite claims by several
companies (incl the major suppliers) several key assays are
significantly affected by this common serum protein (some depressed,
a few enhanced). A so-called ³oligo-clonal² system exists, however
this is far from perfect and can consist of just 3 antibodies (not-
very-oligo-clonal !). If you want to know more re a2M studies in
cytokine ELISAs then ask and I¹ll point you in the right direction.
Many of the companies use anti-body pairs from a common source, so the
assay should be almost identical despite a considerable difference in
price, eg Amersham and R&D systems. Go to the primary producer, if
possible.
If buying more than a few kits ALWAYS negotiate a discount. Never
pay list price...these things can gobble up $1500 for 120 samples in
duplicate so unless you are filthy-rich etc.
Finally, consider obtaining anti-body pairs from some companies
(including Bradsure, UK). These tested antibodies can give you
excellent assays and reduce costs to 10% list....OR....approach the
big companies (eg Genentech etc) who frequently release matched and
QC'd reagents providing you agree to their terms.
Best of luck...Andrew
