Autoantibody Biomarker Discovery

Drug Companion
Diagnostics

Infectious Diseases &
Vaccines

Protein Interaction
Assays

Autoantibody biomarkers for early diagnosis of cancer, autoimmune diseases and other autoimmune dysfunction.

In addition to producing antibodies against foreign molecules, the immune system generates antibodies to self-antigens (“autoantibodies”) in response to many pathological processes. Autoantibodies have several properties which make them excellent indicators of disease and their detection forms the basis of many in vitro diagnostic tests. It is believed that autoantibodies are generated through over-expression, mutation, release of proteins from damaged tissues, mis-folding or mis-presentation of proteins which leads to their recognition by the immune system.

Unlike other serological targets, autoantibodies are stable, highly specific, easily purified from serum, and are readily detectable with well-validated secondary reagents. Due to their inherent amplification within the immune system, autoantibodies are relatively abundant and are easily measured, making them ideal for early diagnosis of disease. The Sengenics IMMUNOME™ protein array has been successfully used to identify predictive, pathologic and protective biomarkers for cancers, autoimmune diseases and other autoimmune dysfunction.

Sengenics autoantibody biomarker discovery assay protocol

Published study:

Autoantibody Biomarker Discovery for Prostate Cancer using a miniaturised version of the IMMUNOMETM array; CT100+ array.(Adeola, H, et. al., 2016)

The study aimed to elucidate the role of 123 Tumour Associated Antigens (TAAs) using antigen microarray platform in blood samples from 20 PCa, 32 Benign prostatic hyperplasia (BPH) and 15 disease control (DC) cohorts. Linear quantitation identified four antigens; GAGE1, ROPN1, SPANXA1 and PRKCZ which have higher autoantibody titres in PCa serum as compared with BPH where MAGEB1 and PRKCZ were highly expressed.

Autoantibody biomarker-based drug companion diagnostics for stratifying patients in terms of responders and/or adverse reactions to cancer immunotherapy and other drugs in various diseases.

Very often, the effectiveness of administered drugs varies from patient to patient due to the complex and heterogenous nature of most diseases, as well as immune system differences in each individual. In fact, some patients, depending on their physiological and immunological makeup, may suffer from immune-related adverse events (irAE) from therapies. Recently, autoantibody-based immunotoxicity profiling has been gaining attention due to its ability to:

  • identify patients who are most likely to benefit from a particular therapeutic product;

  • identify patients likely to be at increased risk for serious side effects as a result of treatment with a particular therapeutic product; or

  • monitor response to treatment with a particular therapeutic product for the purpose of adjusting treatment to achieve improved safety or effectiveness.

If the diagnostic test is inaccurate, then the treatment decision based on that test may not be optimal. It is in this regard that our protein array technology can provide a unique and high throughput method of profiling autoantibodies to investigate the effectiveness of treatment, adverse effects, and the order of use of drugs.

The test can help healthcare professionals determine whether a particular therapeutic product’s benefits to patients will outweigh any potential serious side effects or risks.

Image adapted from: http://www.mbl.co.jp/e/products/companion_diagnostics/

Published study:

Development of a novel, quantitative protein microarray platform for the multiplexed serological analysis of autoantibodies to cancer-testis antigens (Beeton-Kempen N, et. al., 2014)

The IMMUNOMETM protein array was utilised to monitor the treatment responses of metastatic melanoma patients.  The study aimed to explore responses to an experimental therapy, NY-ESO-1, in 46 stage III and IV malignant melanoma patients. Serum samples were collected at time points before receiving vaccination (Day 0) and then 2 weeks after further vaccination boosters (e.g. Days 70 and 54). Melanoma patients’ autoantibody profiles were also compared to that of healthy normal individuals. As expected, the NY-ESO-1 vaccine antigen on the array showed the most significant overall autoantibody binding intensities in approximately 61% of patients. In addition, autoantibody responses to CTAG2 (also known as LAGE-1/NY-ESO-2) were observed in a similar number of patients to NY-ESO-1. Over the course of the treatment, autoantibody responses towards NY-ESO1 and CTAG2 were found to have increased with time points (Day 0 and after further boosters).

Custom arrays spotted with viral and bacterial antigens for infectious disease diagnosis, vaccine efficacy determination and clinical vaccine trial for monitoring population screening.

Viral infections are mediated by several protein–protein interactions. Protein domains are basic units defining protein interactions and mutations at protein interfaces can reduce or increase their binding affinities by changing protein electrostatics and structural properties. During the course of a viral infection, both pathogen and cellular proteins are constantly competing for binding partners. Endogenous interfaces mediating intraspecific interactions—viral–viral or host–host interactions—are constantly targeted and inhibited by exogenous interfaces mediating viral–host interactions. Blocking such interactions is the main mechanism underlying antiviral therapies. A KREXTM-based protein array consisting of antigens from different bacterial/viral strains can be developed and used to evaluate human sera. The array will allow simultaneous examination of the magnitude of antibody responses, the isotype of such antibodies, and the breadth of the bacterial/viral strain recognition.

 

A good vaccine candidate should be able to disrupt, block or inhibit the interaction that induces virulency.

Ongoing Study:

Protein X is the outer membrane protein (OMP) of Bacteria Z, key to the pathogenesis of Bacteria Z infection, it is therefore important as a potential vaccine candidate. The aim is to develop Protein X-based vaccine that can elicit serum bactericidal antibodies capable of suppressing Bacteria Z virulence. The strategy involves detection and evaluation of Bacteria Z outer membrane protein, protein X, as a vaccine component. The expected outcome from the study is high efficacy vaccine candidate for Bacteria Z infection.

Protein interaction assays

Proteins are the workhorses that facilitate most biological processes including cell growth, proliferation, intercellular communication and apoptosis. Proteins interact with other proteins, antibodies, nucleic acids, small molecules and lipids, and these interactions allow biochemical events to take place to regulate all these processes. Any disorders in these interactions can lead to disease.

Exploratory analyses with a variety of analytes can help elucidate protein relationships and interactions that control functionally significant molecular events in cellular pathways.

Published study:

DNA-binding analysis using a p53 protein microarray (Boutell, J.M. et. al., 2004)

Protein-protein interactions between p53 variants and, i) a regulatory onco-protein, ii) a regulatory kinase resulting in on-chip phosphorylation. Proteins with mutations outside of the DNA-binding domain generally had near wild-type affinity for DNA. By contrast, total loss of binding was observed for mutations resulting in truncated proteins and mutations that monomerise the protein.

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