Is it possible to use glucose meters to evaluate immunity against COVID-19?

Is it possible to use glucose meters to evaluate immunity against COVID-19? ...

Researchers at Johns Hopkins University have developed a new rapid assay that can detect SARS-CoV-2 antibodies using widely-available glucose meters. This innovative glucose meter-based antibody assay is easier to perform and more cost-effective than the actual gold-standard assays.

According to one of the authors, Dr. Jamie Spangler, a professor at Johns Hopkins University, has demonstrated an innovative approach to democratizing the availability of immune protection data by enlisting commercial glucometers to quantitatively measure antibodies levels.

According to Dr. Eliah Aronoff, a professor of medicine at the University of California in San Diego, fieldable diagnostics are being developed, but studies such as these highlight a possibility that home diagnosis is as inexpensive and precise as glucose detection. At this point, we will have a transform in global surveillance and personal illness detection.

The study was published in the Journal of the American Chemical Society.

Quantifying antibody levels

Assays for detecting COVID-19 detect the presence of viral genetic material or proteins. Entries for measuring antibodies against SARS-CoV-2 may be helpful in assessing previous exposure to the virus.

These antibodies include IgG antibodies, which are the predominant type of antibodies present in the blood. IgG antibodies play a vital role in producing an immune response against bacteria and viruses, including SARS-CoV-2.

Notably, these IgG antibodies persist for months following a SARS-CoV-2 infection or after receiving a COVID-19 vaccination.

The IgG antibody levels are indicating the degree of protection against a symptomatic SARS-CoV-2 infection. Consequently, assessing antibody levels in the population can help determine how long immunity against COVID-19 persists after vaccination or a previous infection.

A rise of fresh SARS-CoV-2 variants has also raised fears about weak immunity, making it crucial to assess immunity levels in the population. Determining antibodies against SARS-CoV-2 might thus assist in policy decisions.

Because of the need for expensive detection devices, enzyme-linked immunosorbent assays (ELISAs) are the gold standard for measuring antibody levels. However, accurate quantifying antibody levels using ELISAs requires blood samples to be shipped to specialized laboratories. This process is time-consuming, costly, and requires skilled technicians.

Although rapid ELISA tests have been developed for use in the clinic, these tests only provide qualitative information and remain costly. Hence, there is a need for cost-effective and broad accessible alternatives to ELISAs that may be used by clinicians or the general public.

How glucose meters help

Scientists have developed tests that are compatible with glucose meters. Using commercially available glucose meters for antibody detection can reduce the cost of detection and the need for skilled technicians.

These tests involve antibodies or other detection molecules coupled with the enzyme invertase which breaks down sucrose or sugar into glucose. The antibodies coupled with invertase bind to the protein of interest in a sample and produce glucose upon the introduction of a sucrose solution. The amount of glucose produced is proportional to the amount of interest protein and can be detected by a glucose meter.

However, combining antibodies with invertase has proved difficult. In some experiments, researchers combined invertase with antibodies with the help of intermediate compounds such as nanoparticles. However, such an approach may result in a reduced amount of coupling and results.

Researchers at Johns Hopkins University have developed a novel assay involving antibodies that are directly connected with two invertase molecules. These experiments were used in laboratory cultured cells to express these antibodies linked with invertase molecules.

The antibody''s genetic fusion and invertase enzyme ensure that a steady number of invertase molecules are connected to the antibody. These antibodies coupled with invertase can bind to all human IgG antibodies.

The innovative experiment uses a plastic strip covered with the SARS-CoV-2 spike protein. Upon incubation of the strip with blood samples from individuals with a history of COVID-19, the SARS-CoV-2-specific antibodies selectively attach to the spike proteins coating the strip''s surface.

The strip has been re-placed to a solution that includes the antibody-invertase fusion protein and then to a sucrose treatment, following the rinsing of the strip to remove the non-specific antibodies.

The SARS-CoV-2-specific IgG antibodies bound to the spike protein on the strip can then be detected by the antibody-invertase fusion protein. The enzyme then breaks down sucrose into glucose, which can be detected using a glucose meter. The assay produces glucose in proportion to the SARS-CoV-2-specific IgG antibodies in the blood sample.

The researchers found that the glucose meter-based antibody-invertase protein assay would accurately detect IgG antibodies against SARS-CoV-2, and its performance was comparable to commercially available ELISAs.

Potential for other diseases

This antibody-invertase fusion protein has identified all IgG antibodies produced by the human body, thus making this assay more effective.

The immediate objective of this technology is to increase manufacturing so that greater deployment is possible. Dr. Spangler said the researchers will use emerging data from this platform to investigate disease protection and antibody levels across a wide range of subjects.

The method may be used against other situations by coating the strip with a protein other than the wild-type SARS-CoV-2 spike protein. For example, strips coated with the spike protein from a SARS-CoV-2 variant might be used to measure antibody levels against this variant.

We believe that the dosage we have developed may be used to detect antibodies against future forms of the SARS-CoV-2 virus, as well as against other infectious diseases. The assay may also be used to detect antibodies in response to other conditions such as cancer, autoimmune disorders, allergies, or transplantation. Dr. Jamie Spangler

This technique may provide valuable scientific insights and assist in decision-making regarding medical interventions and public health practices. Moreover, the versatility of this platform allows it to be easily adapted to target a wide range of other diseases beyond infection, according to Dr. Spangler.

You may also like: