Technical Performance of our Krex™ Immunome Protein Array

Technical Performance

Exceptional Consistency

Protein arrays made with the KREX technology exhibit exceptional consistency as measured by the coefficient of variation percentage (CV%).

The graph below shows the CV% of intra-protein replicates run on a KREX-based protein array (Immunome) compared to a non-KREX protein array (PX). The mean CV% for Immunome was 7.2% whereas the CV% for protein array PX was 37%.

Very High Specificity

The correct folding of proteins on KREX protein arrays ensures that both continuous and discontinuous epitopes are preserved, hence all antibody binding sites are available. This leads to KREX arrays having very high specificity, and by extension, a high signal-to-noise ratio.

Vastly Superior to Other Autoantibody Platforms

Because all the proteins on KREX protein arrays are correctly folded, conformational as well as non-conformational epitopes are available for binding to antibodies. Since 90% of autoantibody binding sites are conformational in nature, if the protein is not full length or not correctly folded, other protein arrays actually lead to the loss of binding to these conformational epitopes. Using our KREX protein arrays ensure that the binding of antibodies to not just linear, non-conformational epitopes but also discontinuous conformational epitopes.

The main advantage of the KREX-based array is that the immobilised protein is folded in its native conformation, due to the BCCP fusion and the absence of physical protein purification which may affect epitope exposure for recognition.

*90% of autoantibodies bind to conformational epitopes, references:

Barlow, D. J., Edwards, M. S., & Thornton, J. M. (1986). Continuous and discontinuous protein antigenic determinants. Nature, 322(6081), 747–748;
Van Regenmortel, M. H. V. (2006, May). Immunoinformatics may lead to a reappraisal of the nature of B cell epitopes and of the feasibility of synthetic peptide vaccines. Journal of Molecular Recognition, 19(3), 183–187.

Highly Reproducible

KREX-based protein arrays use multiple positive and negative controls to measure reproducibility within, and across, studies and batches.

The graph below shows an almost perfect Pearson correlation of above 0.97 when comparing autoantibody levels across 6,524 protein data points in two different batches.

Picomolar Sensitivity

Autoantibodies on KREX-based protein arrays can be detected at very high sensitivity, only 1 – 10 µl of serum is required. The detection limit is in the 10 pg/ml range, with a linear dynamic range of at least 5 orders of magnitude.