New standardized coating for immune complex ELISAs offered by Bernhard-Nocht-Institute for Tropical Medicine
ELISAs are widely used as a diagnostic tool for the detection of specific antigens or antibodies in e.g. blood specimen. To improve specificity and sensitivity, immune complex (IC) ELISAs for the detection of IgG antibodies have been developed. In this, the solid-phase support is coated with rheumatoid factor (RF), which specifically binds ICs formed during incubation of a labelled antigen and with the serum sample. Since two different immunological mechanisms are involved, IC ELISAs show excellent specificity and very good sensitivity and are technically very simple to perform (only one incubation and washing step).
The widespread use of IC ELISAs has been hampered though by the fact that the RF coating consists of the IgM fraction of sera from various patients with rheumatoid arthritis. Since no recombinant source has been available yet, sufficient supply is not guaranteed and standardization very difficult. To make the superior properties of IC ELISAs available to widespread use, a new coating is needed that can be produced recombinantly.
By comparing various Fc receptor molecules, scientists at the Bernhard-Nocht-Institute for Tropical Medicine have identified an improved coating of the solid-phase support for IC ELISAs. As it turned out, CD32 (FcγRIIA) bind ICs way more efficiently than RF or C1q, and is ideally suited as a coating for IC ELISAs. CD32 is commercially available as a recombinant protein, thus facilitating the desired widespread use and exploitation of IC ELSIAs.
The technology is offered for in-licensing and / or co-development of diagnostic test kits (especially in the field of infectious diseases).
The new coating has been used in IC ELISAs for the detection of IgG antibodies directed against West Nile virus and tick-borne encephalitis (TBE) virus.
A priority establishing European patent application has been filed in 2011.