Innova Biosciences has developed a conjugation technology called Lightning-Link™ (Figure 1) that eliminates almost all of the steps employed in a traditional conjugation process. The elimination of column separations from Innova’s process has probably had the greatest impact. Issues that have beset traditional conjugation procedures—losses of material, sample dilution, batch-to-batch variation and difficulties in scaling up—have now been removed.
The Lightning-Link process is summarized in Figure 2. The researcher pipettes the antibody to be labeled into a vial of lyophilized mixture containing the label of interest. Dissolution of the contents activates the chemicals that mediate the conjugation reaction. Despite its apparent simplicity, the Lightning-Link process is sophisticated and generates conjugates with performance characteristics identical with, or better than, those prepared with laborious multistep conjugation procedures.
Moreover, it is possible to use the resulting Lightning-Link conjugates without purification, as the byproducts of the reaction are completely benign. Because the reactive groups are created in situ in a controlled manner the risk of unwanted polymerization is reduced.
The approach is also tolerant of sodium azide, which is commonly employed as an antimicrobial agent in commercially available antibodies. In addition, BSA, another common additive, has only a modest impact on Lightning-Link conjugation reactions.
This simpler approach to conjugation is likely to shift the balance of indirect detection technologies toward those of direct detection. Researchers carrying out immunodetection procedures can eliminate the tedious secondary incubation and wash steps. Intuitively, one can also see how data quality is likely to be improved by a reduction in the number of assay variables.
In flow cytometry, it is quite common to combine three or more directly labeled primary antibodies, each with a different fluorescent label.
The benefits of simple conjugation technology and direct labeling are even greater in the case of multiplex immunoassay technologies, where large panels of antigen-specific reagents can be constructed from the best available antibody tools, without the usual limitations that apply to indirect detection methods.
Simple conjugation technologies also greatly facilitate conjugate optimization and scale-up.