The cardiac isoform of Troponin I (cTnI) is used as a gold standard as marker of acute myocardial infarction (AMI). The region 24-40 aar of cTnI is a perspective target for monoclonal antibodies (MAb), because it is less affected by the action of autoantibodies and is not hindered by the other components of troponin complex. Majority of this region is also unique to cardiac isoform, which increases the probability of obtaining of highly-specific antibodies without cross-reaction with two skeletal isoforms.
HyTest has developed a new monoclonal antibody technology that is based on rabbit-derived antibodies. One of the company’s core strengths is its considerable experience (25+ years) in hybridoma monoclonal antibody development. The new technology combines the reliability of the hybridoma approach with rapid and flexible gene engineering methods. Our rabbit recombinant antibody technology is based on the natural immune response of rabbits and it includes a robust proprietary protocol for the cloning of target IgG genes to full-size rabbit antibody backbone. Combining a recombinant rabbit MAb with a conventional mouse derived MAb in a sandwich type immunoassays also helps to mitigate the effect of heterophile antibodies.
It is generally considered that rabbit derived antibodies often have higher affinity than mouse derived antibodies. High affinity is especially important in assays where the concentration of the biomarker in sample is very low – such as in the case of cTnI.
HyTest provides four new recombinant rabbit anti-cTnI monoclonal antibodies targeted to the epitope region 24-40 (figure 1) that are designed for development of high-sensitivity cTnI assays. The recombinant rabbit MAbs are available in bulk quantities, which makes them suitable for commercial diagnostic immunoassays. In addition, we developed two murine derived MAbs 1017cc and 1039cc that also show good performance with our existing catalog products.
Figure 1. Region of cardiac troponin I epitope region 24-40.
The cardiac troponin I epitope region 24-40 is widely used as a target in commercial cTnI assays. The new MAbs being paired with antibodies specific to other epitopes can be used for the development of sandwich immunoassays with superior sensitivity limit of detection (LoD) being better than 1 ng/L (figure 2) and high specificity without cross-reaction to cardiac troponin T or to skeletal isoforms of troponin I up to 1 µg/L.
Figure 2. Limit of detection using new recombinant rabbit RecR1 (Cat.# RC4T21) as a capture and 20C6 (Cat.# 4TC2) as a detection.