Sigma-Aldrich
Urea 8 M (after reconstitution with 16 mL high purity water)
U4883
The avidity of antibodies from polyclonal sera to an antigen they have been raised against can be measured via an urea-based ELISA assay. The assay requires high quality urea of known molarity, which is consistent to allow interpolation between avidity ELISA experiments. This Urea, pre-weighed and individually packaged, allows accurate and reproducible avidity ELISAs to be performed.
Avidity ELISA
Individually packed, pre-weighed Urea.
When the individually packed, pre-weighed Urea is reconstituted in 16 ml of high purity water, the final 25 ml solution of urea is of 8M molarity. This solution is then used at 100 ul per well per wash, the wells are washed 3 times, and each wash lasts 5 mins. Control ELISA wells are washed in just high purity water at 100 ul per well per wash, washed 3 times, and each wash lasts 5 mins. The relative OD absorbance between urea and non-urea treated ELISA wells provides the relative avidity of the antigen-specific antibodies.
Vortex the individual bottles following reconstitution with 16 ml water and leave at least 1 hour at room temperature before using.
Consistent results are obtained when using this Urea for the avidity assay. Consistency within treated groups, between experiments and between individuals was observed. Urea can significantly reduce the proportion of antibody bound to its specific antigen when used at 8M concentrations.
None
Availability, price, efficacy, speed of delivery
These pre-weighed and individually packed Urea bottles are simply reconstituted, providing consistent 8M urea solutions for use in antibody avidity ELISAs.