Improving SARS-CoV-2 Antibody Detection with Bioluminescence

3D artistic rendering of the Lumit SARS-CoV-2 antibody test

Science is the practice of figuring out how things work and then using that knowledge to further our understanding or to create tools that can solve problems facing the world. Bioluminescent tools and assays are examples of science doing all these things. Bioluminescence is the light-yielding (luminescence) chemical reaction that is used by many lifeforms. When fireflies flicker in the twilight, they are using bioluminescence to flash on and off.  Chemically, bioluminescence happens when an enzyme called luciferase acts on a light-emitting compound, luciferin, in the presence of adenosine triphosphate (ATP), magnesium and oxygen.

For scientists, bioluminescence can serve as a tool to help them understand many cellular functions. Since few animal or plant cells produce their own light, there is little to no background signal (light) to be concerned about. This lack of background means that all light coming from the sample can be measured. In fact, bioluminescence is often a preferred tool for scientists because it does not require an external light source or special filters, which are required for fluorescence-based technologies.

Promega scientists have developed bioluminescent tools and assays to support leading edge scientific research for decades, beginning in 1990 with the Luciferase biosensor technology based on firefly luciferase. Luciferase is a wonderful tool for studying how enzymes work because its output (light) is so easy to measure: samples are placed into a special instrument called a luminometer, and the amount of light being produced (Relative Light Units) is recorded. Bioluminescence technology can be configured to measure a variety of cellular biology, ranging from cell health to enzyme activity down to the specific event of turning a gene on or off. The advent of new techniques for genetic manipulation, along with an enhanced understanding of bioluminescence and the discovery and engineering of better luciferases, enables science to use bioluminescence in even more unique ways.

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Understanding Inflammation: A Faster, Easier Way to Detect Cytokines in Cells

Inflammation, a process that was meant to defend our body from infection, has been found to contribute to a wide range of diseases, such as chronic inflammation, neurodegenerative disorders—and more recently, COVID-19. The development of new tools and methods to measure inflammation is crucial to help researchers understand these diseases.

This diagram shows how the Lumit™ Immuno assay can be used to detect cytokines.

Cytokines—small signaling molecules that regulate inflammation and immunity—have recently become the focus of inflammation research due to their role in causing severe COVID-19 symptoms. In these severe cases, the patient’s immune system responds to the infection with uncontrolled cytokine release and immune cell activation, called the “cytokine storm”. Although the cytokine storm can be treated using established drugs, more research is needed to understand what causes this severe immune response and why only some patients develop it.

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Drug Repurposing Screens: Redeploying Old Dogs for New Tricks

This blog was written by guest author, Amy Landreman, PhD.

Drug repurposing, identifying new uses for approved or investigational drugs, is an attractive strategy when looking for new disease treatments. Because the compounds have already gone through some level of pre-clinical optimization and safety testing, this approach can reduce risk, reduce cost, and speed up the timeline for further drug development. An additional benefit of this approach is that it can result in new biological insights or a better understanding of disease mechanisms since these compounds usually already have some level of mechanistic characterization. Indeed, there are now a number of compound collections openly available specifically for the purpose of facilitating drug repurposing efforts. For example, the ReFRAME (Repurposing, Focused Rescue, and Accelerated Medchem) library is a collection of 12,000 compounds developed by Scripps Research Center and has been screened to identify novel candidate therapeutics for Cryptosporidium infection (1). The Broad Institute also offers a drug repurposing hub that contains an annotated collection of over 7,000 compounds.

Drug repurposing libraries, although often smaller than novel compound small molecule libraries, are designed for implementation into high-throughput screening workflows in order to efficiently triage compounds for the desired result. Effective compound screens require assays that can be scaled to 384 or 1536-well microplate formats and implemented in batch or continuous processing workflows. The firefly luciferase reaction has been leveraged to create many assays that are well-suited to these types of high-throughput screening approaches. In particular, the generation of “Glow” assays that have stable luminescent signals and homogenous assay design is a good fit. The signal stability allows for multi-plate processing and because the reagent is added directly to cells in culture, pre-processing steps are eliminated allowing for automated workflows. Assay reagents such as the CellTiter-Glo® Cell Viability Assay and the ADP-Glo™ Kinase Assay are commonly used in screening efforts including those done with repurposing libraries.  In addition, there are several firefly luciferase reporter assay reagents such as Steady-Glo® and Bright-Glo™ Luciferase Assays that have been optimized for high-throughput detection of firefly luciferase activity making them well-suited to repurposing screens.

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What Is A Viral Variant?

Every time a genome is replicated, there’s a chance that an error will be introduced. This is true for all life forms. On a small scale, these mutations can lead to genetic diseases or cancers. On a much larger scale, random mutations are an important tool of evolution.

During the COVID-19 pandemic, the SARS-CoV-2 virus has picked up many mutations as it spread around the world. Most of these mutations have been inconsequential – the virus didn’t change in any significant way. Others have given rise to variants such as B.1.1.7 and B.1.351, which present complications for public health efforts. By studying the evolution of the virus, we can monitor how it’s spreading and predict the characteristics of variants as they are detected.

SARS-CoV-2 variant
David Goodsell Painting of SARS-CoV-2 Virus
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A SARS-CoV-2 NanoLuc® Reporter Virus for Rapid Screening of Antivirals

nanoluc invivo imaging

Before the COVID-19 global pandemic began, Dr. Xuping Xie, Assistant Professor of the University of Texas Medical Branch at Galveston, TX has been studying viruses, such as Dengue and Zika, for more than 10 years. Once the pandemic hit in early 2020, he was prepared to join the fight against the virus. “There was an urgent need to know: Is there a quicker way to develop therapeutics or antibodies to target SARS-CoV-2?” says Dr. Xie. “That’s why we immediately launched our SARS-CoV-2 project.”

His goal was to create an assay that could 1) screen for antiviral drugs and 2) quickly measure neutralizing antibody levels. The assay could be used to determine the immune status of previously infected individuals and to evaluate various vaccines under development. To achieve this, he wanted to create a reporter virus that is genetically stable and replicates similarly to the wild-type virus in cell culture. 

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COVID-19 Therapies: Are We There Yet?

A year after COVID-19 was declared a pandemic, collaborative efforts among pharma/biotech and academic researchers have led to remarkable progress in vaccine development. These efforts include novel mRNA vaccine technology, as well as more conventional approaches using adenoviral vectors. While vaccine deployment understandably has captured the spotlight in the fight against COVID-19, there remains an urgent need to develop therapeutic agents directed against SARS-CoV-2.

COVID-19 therapeutic drugs

In the March 12 issue of Science, an editorial by Dr. Francis Collins, director of the U.S. National Institutes of Health (NIH), examines lessons learned over the past 12 months (1). Collins points out that many clinical trials of potential therapeutics were not designed to suit a public health emergency. Some were poorly designed or underpowered, yet they received considerable publicity—as was the case with hydroxychloroquine. Collins advises developing antiviral agents targeted at all major known classes of pathogens, to head off the next potential pandemic before it becomes one. A news feature in the same issue discusses the current state of coronavirus drug development (2).

The present crop of drug candidates is remarkably diverse, including repurposed drugs that were originally developed to treat diseases quite different from COVID-19. Typically, however, the mainstream candidates belong to two broad classes: small-molecule antiviral agents and large-molecule monoclonal antibodies (mAbs).

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Impact of COVID-19 Pandemic on Cancer Diagnosis—When Fewer Cases of Cancer is Not Good News

The year 2020 was a year filled with things we didn’t do. The global COVID-19 pandemic meant we didn’t gather with family and friends; we didn’t attend concerts or sporting events; we didn’t even go to work or school in the same way. We also didn’t go to the doctor, and as a result, many countries and organizations are reporting that there was an alarming drop in the number of new cancer cases (1–6). Unfortunately, while fewer diagnosis might sound like a good thing, there is no evidence that the actual rate of new cancer occurrence is declining (7).  

COVID-19 Restrictions Impact Cancer Screening and Diagnosis

The drop in cancer diagnosis happened after countries began to put into place new restrictions intended to slow the spread of the SARS-CoV-2 virus. These measures often included limiting or pausing many routine screenings and doctor visits, which also limited or paused opportunities to diagnosis cancer. The resulting decline in new cancer diagnosis was dramatic. In the United States, there was a 46.4% decline in the number of newly diagnosed cases of six of the most common cancer types (breast, colorectal, esophageal, gastric, lung and pancreatic) per week between March 1, 2020 and April 18, 2020 (1,2,8).

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From Primate Models to SARS-CoV-2 Sequencing and Testing

As the SARS-CoV-2 virus spread around the world in early 2020, many researchers shifted their focus to support the global endeavors to address the challenge. For two professors at the University of Wisconsin, their efforts started with animal models to study pathogenicity and grew into massive SARS-CoV-2 sequencing and COVID-19 testing projects.

Virologists David and Shelby O'Connor (shown running along Lake Mendota) have worked extensively in SARS-CoV-2 Sequencing and COVID-19 Testing

“Being a scientist in this field gives a sense of purpose, but also a sense of obligation and responsibility,” says David O’Connor, PhD. “You always want to feel like you’re living up to that.”

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Engineering a Safer SARS-CoV-2 for Use in the Research Laboratory

This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals ultrastructural morphology exhibited by coronaviruses such as SARS-CoV-2. Photo Credit: Alissa Eckert, MS; Dan Higgins, MAM CDC
SARS-CoV-2 illustration from CDC; Photo Credit: Alissa Eckert, MS; Dan Higgins, MAM
E = envelope; M = membrane

A worldwide pandemic requires scientific research to understand the viral pathogen. The focused efforts of global scientists are even more necessary in the face of a novel coronavirus like SARS-CoV-2, the causative agent of COVID-19. However, because SARS-CoV-2 causes human disease, research efforts are restricted by the need for physical laboratories that are equipped to handle the required level of containment and personnel trained to handle pathogens in these facilities. But what if we could bypass the restrictive facility requirements by engineering a synthetic, replication-defective version of SARS-CoV-2 that more researchers could use to study the pandemic coronavirus, expanding the capacity to test and develop methods to attenuate its devastating effect on humans?

The challenge is to develop a derivative of SARS-CoV-2 that reflects how it behaves in the cell but is compromised such that it is unable to infect cells more than a single time. That is, the virus can get into a cell or be introduced into cells and replicate but is unable to produce infectious virus would offer a pathway to expand research capacity without the use of special laboratory facilities. This replication-defective SARS-CoV-2 could be created to encode as much or as little of the genome needed to examine its lifecycle without becoming a fully infectious virus. In fact, this replication-defective version of SARS-CoV-2 could include additional genetic elements that could be used to control its expression, track the virus in cells and measure the level of its replication. This task has been undertaken by Dr. Bill Sudgen’s group at the University of Wisconsin–Madison McArdle Laboratory for Cancer Research, explained by graduate student Rebecca Hutcheson during her presentation “Making the Virus Causing COVID-19 Safe for Research”.

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Buckling Down to Scale Up: Providing Support Through the Pandemic

The past year has been a challenge. Amidst the pandemic, we’re thankful for the tireless work of our dedicated employees. With their support, we have continuously stayed engaged and prepared during all stages of the COVID-19 pandemic so that we can serve our customers at the highest levels.

How We Got Here

The persistent work by our teams has made a great impact on the support we can provide for scientists and our community during the pandemic. From scaling up manufacturing to investing in new automation, every effort has helped.

Promega has a long history of manufacturing reagents, assays, and benchtop instruments for both researching and testing viruses. When the pandemic began in 2020, we responded quickly and efficiently to unprecedented demands. In the past year, we experienced an approximately 10-fold increase in demand for finished catalog and custom products for COVID-19 testing. In response to these demands, we increased production lines. One year ago, we ran one shift five days per week. Currently, we run three shifts seven days per week. This change has allowed 50 different Promega products to support SARS-CoV-2 testing globally in hospitals, clinical diagnostic laboratories, and molecular diagnostic manufacturers. Additionally, our clinical diagnostics materials make up about 2/3 of COVID-19 PCR tests on the global market today. Since January 2020, Promega has supplied enough reagents to enable testing an estimated 700 million samples for SARS-CoV-2 worldwide.

Developments and Advances

Promega products are used in viral and vaccine research. This year, our technologies have been leveraged for virtually every step of pandemic response from understanding SARS-CoV-2 to testing to research studies looking at vaccine response.

Promega product: The Lumit™ Dx SARS-CoV-2 Immunoassay

Who Got Us Here

We are extremely grateful for our employees. In the past year, we hired over 100 people and still have positions open today. While welcoming newcomers, this challenging year also reinforced the importance of our collaborative culture. Relationships at Promega have been built over multiple years. The long history of our teams allows us to stay coordinated while prioritizing product distribution to customers across the globe. It also leads to effective communication with colleagues and vendors. Those leading our manufacturing operations team, for example, have an average tenure of 15 years. Their history in collaborating through challenging situations helps them quickly focus where needed most.

Our 600 on-site employees support product manufacturing, quality, and R&D. They do it all while remaining COVID-conscious by social distancing, wearing masks, working split shifts, and restricting movement between buildings. While we continue to practice physical safety precautions, we also prioritize our employees’ mental health and wellness. Promega provides a variety of wellness resources including phone and video mental health sessions, virtual fitness and nutrition classes, and stress and anxiety tools.

What’s to Come

While we acknowledge that the COVID-19 is not over, we are proud of the support we have been able to provide to customers working both on pandemic research and critical research not related to COVID-19. Our policies of long-term planning and investing in the future has allowed us to respond quickly and creatively and learn from the experience.


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