Avian Antibodies with an Edge of Quality

By LabMedica International staff writers
Posted on 24 Sep 2015
New chicken IgY antibodies with SPRi validation of specificity and affinity provide an advantage in choosing antibodies for research and for development of diagnostic tests.

In specific applications chicken IgY antibodies constitute an advantageous alternative to their commonly used mammalian equivalents. Larger phylogenetic distance, higher productivity, and larger antibody yields are just some of the examples. Sanovo Biotech A/S (Odense, Denmark) specializes in development and thorough characterization of polyclonal avian antibodies for diagnostic and research purposes. The antibodies are developed from a broad range of antigens such as whole human proteins, recombinant proteins expressed in different vectors, protein fragments, and peptides.

Image: For five (1-5) diagnostic antibodies: specific-binding curves of Total IgY in a complex protein solution binding to immobilized antigen. Data provide direct information about the specificity of three different production batches, highly valuable information especially for development of diagnostic assays. Curves for all antigen spots are shown. Binding of IgY is observed only to its respective immobilized antigen. (Photo courtesy of Sanovo Biotech).

A one-step purification technology enables isolation with high purity (≥95%) in commercial quantities. The process is quick, free from toxic chemicals, and results in high volumes of concentrated antibody. Further affinity purification against the target molecule generates a specific polyclonal antibody fraction of superior purity.

A common disadvantage of commercially available antibodies is lack of detailed information about affinity, avidity, and specificity. In many cases such information is crucial for successful development of immuno-diagnostic techniques. Therefore Sanovo Biotech has acquired a platform for a detailed characterization of avian antibodies and established strong collaboration with the University of Southern Denmark in order to investigate the abovementioned factors. SPRi analyses were performed by Jonas Borch-Jensen, Villum Center for Bioanalytical Sciences, University of Southern Denmark. In this way Sanovo Biotech provides customers with batch-to-batch consistent and well-characterized products.

The main challenge in validating a diagnostic antibody is confirmation of its specificity. Commonly used methods such as ELISA, Dot Blot, or Western Blot visualize the antigen-antibody complex but do not provide information about specific interaction over time. Sanovo Biotech products are characterized by SPRi to provide detailed information about the uniformity of different batches, kinetics of antigen-antibody complex, expected avidity, and even apparent affinity constants.

Antibodies are available for: CRP (C-Reactive Protein)-inflammation marker, Myoglobin-cardiac failure marker, D-Dimer-Thrombosis marker, Lipoprotein(a)-coronary disease marker, Cystatin C-kidney function marker, and Rhodopsin-diabetes marker. Several additional diagnostic and research products under development will soon be available. Diagnostic antibody products have been validated as both “Total IgY” preparations (complete IgY fraction isolated from egg yolk containing the specific antibody) and affinity-purified preparations.

Comparative kinetic data analyses of affinity-purified antibodies provide valuable information, important especially for diagnostic application. From different egg collection times binding kinetics are almost identical, confirming excellent uniformity between the batches. Antibodies bind specifically and stably to their antigens (half-life of the complex estimated in the hours range).

Successful SPRi experiments can also identify the exact amount of antibody immobilized on the sensor that recognizes a known molar concentration of the relevant antigen. Such information might be useful when a detection threshold for designing and developing a diagnostic test has to be identified. Sanovo Biotech antibodies can be tested in amounts and formulations specified by the customer in order to provide the required level of kinetic data.

It can be concluded that SPRi analysis of avian antibodies provides valuable information for improving theoretical predictions in immuno-assay development and thereby for providing a much more reliable analytical and diagnostic antibody tool.

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