Seramun Diagnostica GmbH

The entry of SARS-CoV-2 into its target cells depends on binding between the receptor-binding domain (RBD) of the viral spike protein and its cellular receptor, angiotensin-converting enzyme 2. Many investigations show a clear correlation between the presence of neutralizing antibodies and the detection of RBD-specific antibodies. To improve the SARS-CoV-2 antibody diagnostic and the detection of potentially neutralizing or protective antibodies, the Seramun Diagnostica GmbH has successfully developed an ELISA which is able to detect SARS-CoV-2-RBD-specific IgG antibodies. This Anti-SARS-CoV-2-RBD ELISA has so far been tested with 64 sera of COVID-19 patients and 218 negative blood donor sera (incl. Control groups → CMV, EBV, HBV, HCV, RF, pregnant woman). A Sensitivity of 90.6% and specificity of 100% were determined. RBD is a highly specific antigen for the SARS-CoV-2-antibody diagnostic. Antibody-crossreactivities with other human- and animal-pathogenic coronaviruses are unlikely. Semi-quantification of RBD-specific antibodies is possible with the assay and of increasing importance in the context of vaccination control. Furthermore, the assay is applicable for animal sera e.g. monkey, mouse, and hamster for vaccine-, drug-research and veterinary research.

The Seramun Diagnostica GmbH developed two macroarrays for the SARS-CoV-2 antibody diagnostic. The SeraSpot® Anti-SARS-CoV-2 IgG and IgA assay contains a total of 4 different SARS-CoV-2-specific antigens (nucleocapsid protein, spike protein, spike S1 domain, receptor binding domain). With this product the independent detection of NP-, Spike-, Spike-S1- and RBD- IgG or IgA antibodies from one sample in one well is possible. The detection of different antibodies could be interesting to determine potential risk infections, to discriminate active from past infections, for antibody profiling or to detect possible protective antibodies. The SeraSpot microarray could greatly increase the specificity of the SARS-CoV-2 serological diagnostic. Both assays could be applicable as SARS-CoV-2 confirmation test for the serology diagnostic.

The ready-to-use TMB substrates of the SeramunBlau® line include products for colorimetric ELISA applications as well as for membrane immunoassays and microarrays. The precipitating substrates form color complexes which clearly stand out against the pale background color. All substrates are based on the enzymatic reaction of horseradish peroxidase. SeramunGelb® products can be used for colorimetric ELISA application while SeramunPurple® prec, being used in the membrane area, offers a high color contrast and stable dark red precipitates through AP-based turnover reactions.

Seramun stabilizers are being used for stabilization of HRP and AP conjugates as well as for stabilization of biomolecules and sensitive protein mixtures. Protein-free stabilizers such as SeramunBlock NP 5x conc. strongly reduce the background effects of biological components and are therefore an important part of the Seramun Diagnostica product range.

The Seramun antibody service offers production, purification and labeling of poly- and monoclonal antibodies. For this purpose, Seramun has a modern animal husbandry. Required immunization antigens are produced directly on site in the antigen service area. For this purpose, Seramun is working with different expression systems. Different methods for purifying the antigens and antibodies are available. The reactivity of the generated antibodies is checked via ELISA. A comprehensive quality control of the antigens is carried out at the Seramun premises.