Engineered cells for anti-RBC, anti-neutrophil and anti-platelet antibody detection, identification and depletion
Prof. Halvard Bönig, Goethe University Frankfurt am Main and German Red Cross Blood Service BaWüHe; Eliza Wiercinska, German Red Cross Blood Service BaWüHe; Dr Nikolas Ryschka, Goethe University Frankfurt am Main
More than 400 different polymorphic blood group antigens in more than 30 systems alone are expressed on erythrocytes; similarly platelets and neutrophils express polymorphic antigens, the human platelet and neutrophil antigens, HPA and HNA. All current standard immunohematology tests use panels of primary cells – erythrocytes, neutrophils, platelets – as antigen carriers which are then probed with patient sera, and secondary antibodies are used for detection. Patterns of positive and negative reactions are then interpreted to identify the specificity of the antibody and to avoid the cognate antigen in the transfusion product. Available technology fails when several antibody specificities are present, or antibodies against frequent or non-polymorphic antigens, or pseudo-agglutination occurs, as well as antibodies against rare blood group antigens will be overlooked because they may not be represented in the panel. Moreover, several medicinal antibodies for tumorimmunotherapy bind to and agglutinate blood cells, yielding false-positive reactions and thus rendering blind currently available immunohematology tests. Latex bead-bound antigens as have been very useful for anti-HLA antibody testing are not suitable for the majority of blood group antigens because of their complex structure as membrane proteins.
We proposed to express on a non-human cell a minimum of human proteins, a single protein whenever possible, with only one polymorphic site. In proteins bearing more than one polymorphism, we will generate antigenically neutral, synthetic variants or, if technically not possible, generate all possible combinations of polymorphisms. Patient sera will be incubated with these engineered antigen-bearing cells. If they contain a cognate antibody, subsequent incubation with a secondary anti-huIgG antibody with a detectable label will allow specification of the antibody. The technology is equally suitable for depletion of medicinal antibodies from patient plasma to facilitate conventional immunohematological testing.
Licensing or assignment of the IP to a company invested in the field of immunohematology is preferred. The inventors offer to support further development of market-ready applications for the technology if desired. The owners of the IP will also consider other forms of collaboration, for instance with the investor sharing costs of development and taking responsibility for world-wide marketing of the product line(s), while the inventors could continue to develop applications and manufacture and certify reagent batches.
Two products, FNAIT-ID for rapid platelet antibody identification for FNAIT-patients and Darasorb, a Daratumumab absorption reagent for pre-analytic treatment of plasma from Multiple Myeloma patients, have been developed to prototype status, test cells for more than a dozen blood group antigens were generated for proof-of-concept documentation.
International PCT patent application no. PCT/EP2016/053989 filed on Febr. 25th, 2016, national proceedings in EP (intention to grant a patent), US (intentiont to grant a patent), JP, CA