Protein Development and Production Unit: Diagnostics Development
IBGRL Diagnostics Development aims to extend our knowledge of the production, structure and function of recombinant antibody and antigen molecules and to translate this into improved, next-generation diagnostic reagents. We use a combination of molecular biology, structural biology (biophysics), biochemical and cell culture techniques to develop reagents for diagnostic and research use in blood transfusion practice and organ transplantation. This includes providing analytical tools to support protein or cellular therapies (antibody therapeutics and Advanced Cellular Therapies, respectively).
Antigen Engineering offers a service to NHSBT, the NHS and external customers to produce clinically significant antigens as antigenically active recombinant molecules.Such molecules can be immobilised on solid-phase platforms to allow the sensitive detection, specific identification and accurate quantitation of, for example, blood group specific antibodies in transfusion and transplant recipients and expectant mothers. The next generation systems should be more sensitive, specific and rapid than current methods which are based on selected red cell panels for antibody screening and identification.Kell, Duffy, Lutheran, Knops, and MNSs system antigens have already been successfully produced.
In addition to red cell antigens, we also work on recombinant platelet and granulocyte antigens and cell lines for use in diagnostic tests for HPA- and HNA-specific antibodies.
We have also been working on improvements to existing red cell diagnostic assays and have developed a flow cytometry method for the accurate quantitation of anti-D and anti-c antibodies during pregnancy.We have successfully introduced soluble recombinant CR1 protein (Knops Inhibition Reagent KNIR) into RCI labs where it is used to remove “nuisance” antibodies from patient samples, enabling more rapid identification of underlying clinically significant antibodies.
Antibody engineering amalgamates traditional protein engineering techniques (protein chemistry) with new biophysical approaches in order to achieve the desired properties of the reagents. Numerous recombinant platforms have been established to modify existing antibody specificities and/or graft onto the molecule of choice. This also involves the generation of IgM antibodies from existing cell lines producing IgG antibodies, and the generation of new cell lines by cloning antibody variable region cDNA (extracted from peripheral blood lymphocytes) –and expressing these as recombinant IgM molecules in mammalian cell lines. In silico approaches are employed to study the dynamic properties of the residues critical for antibody variable region binding to antigen. Information from molecular modelling can be used to engineer antibodies with new variable region sequences with improved or modified antigen binding characteristics.