Monitoring Autoimmune Responses
Identifying the antigens that elicit an autoimmune response can yield panels of biomarkers used to classify disease, predict patient outcomes, and characterize leads. Researchers from Life Technologies presented data from studies with the firm’s high-content ProtoArray and new ProtoPlex platforms demonstrating assay robustness and offering study design tips.
Niro Ramachandran, Ph.D., R&D manager, discussed work with protein microarrays composed of up to 9,000 purified full-length human proteins to evaluate immunological profiles across panels of serum samples. The goal was to identify biomarkers for SLE diagnosis, mesothelioma, and early detection of colorectal cancer.
Instead of printing antibodies on the slide as is often done, ProtoArray entails printing functional proteins, such as transcriptional factors, on the glass.
“It’s fundamentally a discovery tool designed to screen one-third of the proteome,” said Dr. Ramachandran.
The first coarse screening is done with ProtoArray followed by ProtoPlex, using Luminex xMAP technology, for high-throughput characterization of promising makers.
“ProtoPlex is similar to an ELISA technology except with ELISA you can test just one reaction in a well, i.e., one antigen or antibody. Luminex offers these color-coded beads that you can put different antigens on and the color can be read so it’s addressable.
“We can take 50 of these different beads and 50 different proteins and put them all in the same well and from one well you can pass serum against 50 antigens,” said Dr. Ramachandran, adding the concordance between the two platforms is around 70%, higher than mass spec.
Companies also use the platform to screen small molecules seeking protein binding information to help reveal mechanisms of action and identify leads and targets.