Immunoaffinity Capillary Electrophoresis in the Era of Proteoforms, Liquid Biopsy and Preventive Medicine: A Potential Impact in the Diagnosis and Monitoring of Disease Progression

Abstract

Over the years, multiple biomarkers have been used to aid in disease screening, diagnosis, prognosis, and response to therapy. As of late, protein biomarkers are gaining strength in their role for early disease diagnosis and prognosis in part due to the advancements in identification and characterization of a distinct functional pool of proteins known as proteoforms. Proteoforms are defined as all of the different molecular forms of a protein derived from a single gene caused by genetic variations, alternative spliced RNA transcripts and post-translational modifications. Monitoring the structural changes of each proteoform of a particular protein is essential to elucidate the complex molecular mechanisms that guide the course of disease. Clinical proteomics therefore holds the potential to offer further insight into disease pathology, progression, and prevention. Nevertheless, more technologically advanced diagnostic methods are needed to improve the reliability and clinical applicability of proteomics in preventive medicine. In this manuscript, we review the use of immunoaffinity capillary electrophoresis (IACE) as an emerging powerful diagnostic tool to isolate, separate, detect and characterize proteoform biomarkers obtained from liquid biopsy. IACE is an affinity capture-separation technology capable of isolating, concentrating and analyzing a wide range of biomarkers present in biological fluids. Isolation and concentration of target analytes is accomplished through binding to one or more biorecognition affinity ligands immobilized to a solid support, while separation and analysis are achieved by high-resolution capillary electrophoresis (CE) coupled to one or more detectors. IACE has the potential to generate rapid results with significant accuracy, leading to reliability and reproducibility in diagnosing and monitoring disease. Additionally, IACE has the capability of monitoring the efficacy of therapeutic agents by quantifying companion and complementary protein biomarkers. With advancements in telemedicine and artificial intelligence, the implementation of proteoform biomarker detection and analysis may significantly improve our capacity to identify medical conditions early and intervene in ways that improve health outcomes for individuals and populations.

A Case Report of a COVID-19 Infection with Positive Sputum and Negative Nasopharyngeal Rapid Antigen-Based Testing: A Practical Method to Explore Sputome

“…Advancements in finding effective therapies and vaccines should also be hand-in-hand with new and error-free diagnostic assessment. Although point-of-care tests are the most desirable alternative to ramp up large-scale population screening, analytical separation technologies coupled to selective affinity-capture methods and powerful detectors, such as laser-induced fluorescence and mass spectrometry are becoming vital tools for isolation, separation, identification, and structural characterization of molecular viral and other pathogens entities [9,[67][68][69][70][71][72][73]. Infectious diseases do not respect international boundaries.…”

“…It is often quite laborious to screen for the correct antibody pairs, and their binding need to be specific enough to avoid cross-reaction with other forms of coronavirus that have highly homologous functional domains [8]. It has previously been discussed [9] that immunoassays are prone to generate false positive results due to the polyreactivity of antibodies and antibody-like molecules. One of the most prominent causes of antibody cross-reactivity or multispecificity is molecular mimicry.…”

“…Molecular mimicry is structural, functional, or immunological similarities shared between macromolecules found in infectious pathogens and in host tissues. Therefore, a false positive can result from binding a substance different from the one of interest due to structural similarities in its antigens [9].…”

Advancements in Oncoproteomics Technologies: Treading toward Translation into Clinical Practice

“…IACE uses antibodies as affinity reagents, however other variants have emerged that use various ligands/probes (e.g., lectins, aptamers, and metalorganics), for selective capturing of the target. IACE coupled with MS has been used for mapping proteoform in various studies [ 335 , 336 , 337 ]. It is used as a point-of-care instrument to profile proteoform patterns in biological fluids, and in proteins obtained from tumor cells, exosomes, or vesicles present in biofluids [ 336 , 337 , 338 , 339 , 340 , 341 ].…”

“…IACE coupled with MS has been used for mapping proteoform in various studies [ 335 , 336 , 337 ]. It is used as a point-of-care instrument to profile proteoform patterns in biological fluids, and in proteins obtained from tumor cells, exosomes, or vesicles present in biofluids [ 336 , 337 , 338 , 339 , 340 , 341 ].…”