This post is written by guest blogger, Melanie Dart, PhD, Sr. Research Scientist at Promega.
Along with lockdowns and sheltering in place efforts, the COVID-19 pandemic brought a unique challenge to our doorstep this spring: developing a clinical serological test for COVID-19 to detect the presence of antibodies against the SARS-CoV-2 virus. The project was one of the fastest, most dynamic development efforts ever undertaken at Promega. In general, in vitro diagnostic (IVD) tests take at least one to two years to develop. Nothing about 2020, however, has been typical.
It was important to move quickly. We set an aggressive timeline, and to meet it we needed not only dedication of our internal team, but also contributions from the local community.
Antibody tests are often used to determine whether individuals have been exposed to certain bacteria or viruses. For most existing antibody tests, the process goes something like this: A vial of blood is drawn from the individual, the vial is sent to a lab, then a trained technicians performs the antibody test and sends back the results. The current process is less than ideal for a few reasons. For one, blood draws are invasive and can be painful. Also, getting results could take days due to the time required to deliver and process the sample. Lastly, costs can be high, since the need for trained professionals and specialized instruments in laboratory settings adds to the cost of each test.
What if all you needed to do for an antibody test was apply a single drop of blood onto a thin piece of film, and you would get results on the spot within five minutes? Scientists have recently developed an antibody test based on bioluminescent technology that could make this a reality. They describe their findings in a recent study published in ACS Sensors.
Our skin, respiratory system and gastrointestinal tract are continually bombarded by environmental challenges from potential pathogens like SARS-CoV-2. Yet, these exposures do not often cause illness because our immune system protects us. The human immune system is complex. It has both rapid, non-specific responses to injury and disease as well as long-term, pathogen-specific responses. Understanding how the immune response works helps us understand how some pathogens get past it and how to stop that from happening. It also provides key information to help us develop safe and effective vaccines.
The immune response involves two complementary pathways: Innate Immunity and Adaptive Immunity. Innate immunity is non-specific, rapid and occurs quickly after an injury or infection. As a result of the innate immune response, cytokines (small signaling molecules) are secreted to recruit immune cells to an injury or infection site. Innate immunity does not develop “memory” of an antigen or confer long-term immunity.
The immune response involves to complementary pathways: Innate Immunity and Adaptive Immunity.
Unlike innate immunity, adaptive immunity is both antigen-dependent and antigen-specific, meaning that adaptive immune response requires the presence of a triggering antigen—something like a spike protein on the surface of a virus. The adaptive immune response is also specific to the antigen that triggers the response. The adaptive immune response takes longer to develop, but it has the capacity for memory in the form of memory B and T cells. This memory is what enables a fast, specific immune response (immunity) upon subsequent exposure to the antigen.
From the beginning of this pandemic, scientists around the world have been working around the clock in pursuit of answers that can effectively combat the SARS-CoV-2 virus. One of hardest things for people to grapple with, is all the unknowns: When will this end? When can I safely visit my friends and family again? What if I have it or had it and I don’t even know it?
The increased availability of serological testing has helped ease people’s minds about their personal COVID-19 status. From a distance, serological testing may seem like a huge milestone in the marathon that is this pandemic. Unfortunately, many of these tests provide murky and inconsistent results.
Today’s blog is written by Ashley G. Anderson, MD, Chief Medical Officer at Promega.
The need for reliable virus detection methods is central to the global response to COVID-19. These test results not only inform health decisions for individual patients, but they also help us build projections of how the virus will spread, which can in turn influence policy decisions.
Following the emergence of COVID-19, PCR-based tests were developed and deployed to detect the virus in patients in hospitals. PCR, or Polymerase Chain Reaction, is a common technique used in labs to amplify large quantities of DNA. The detection tests use swabs placed deep into the back of the nose to detect genetic material carried by SARS-CoV-2, the virus causing COVID-19.
Those tests have been crucial to monitoring infection rates and informing patient treatment, but at this point they have fallen short of providing an overall picture of the pandemic. We know that thousands more cases have likely gone untested due to mild or unnoticed symptoms or lack of access to tests. Since PCR-based methods can only tell us if the virus is active in the patient at the time of sample and offer no information about whether a patient has been infected in the past, we currently have no way to determine how many of these unconfirmed cases exist or which patients have recovered. Serological assays are the one of the most promising tools to address that question.