Learning so much about COVID-19, at the microscopic level, has been scary, but it has also been helpful. Knowing how viruses spread has also afforded me the knowledge of what steps to take to protect myself and my family. It has also been reassuring to learn about our innate and immune responses and to know that there are cellular processes going on every moment to protect me from invaders. Another thing that we have learned about is antibodies and the role that they play in the immune response, whether it is to SARS-CoV-2 or to the flu. Antibodies are also useful to use because they can be used in diagnostic tests. We can examine things like the presence of antibodies in our blood, as well as their type to determine whether or not we have been infected with SARS-CoV-2 and/or if we have been exposed to it in the past.
The two antibody types that tell us the most about an infection are IgG and IgM. Both of these are eventually synthesized to combat infections, but they are synthesized at distinct stages throughout and after the course of infections. IgM is the first antibody made in response to an infection, whereas IgG is made later in the infection and is long-lived, so it remains in the blood even after recovery. Generally, having just IgM antibodies indicated an active infection, so you are still contagious. Having only IgG antibodies often indicates a past infection, but when present with IgM it can indicate a current infection and that you are still contagious. If you only have IgG, though, this is more likely to mean that you have been infected sometime in the past and that your body has mounted a successful immune response to eliminate the infection.
Now, why would being able to test for antibodies help us understand COVID-19 more clearly? Well, if we were able to determine people who have been infected with and recovered from SARS-CoV-2 infections, we can start piecing things together (Kossakovski, n.p.) For example, are there any risk groups? Are there any groups that have a much higher rate of survival? Is it possible that our bodies can form long lasting immunity against SARS-CoV-2? Not only that but studying and isolating antibodies from people who have recovered from COVID-19 could lead to potential treatments, since they are being taken from a body that has successfully fought off the virus (Kossakovski, n.p.) With so much value in antibody titers, there are several US companies working to get FDA approval for tests they have developed. One test developed by Cellex in RTP has been approved for “emergency use” by the FDA, which is a step towards being the first titer to gain FDA approval (Saplakoglu, n.p.) This “rapid test” takes about 15 to 20 minutes and assesses IgG and IgM in serum (Saplakoglu, n.p.), which is already faster than some current diagnostic methods and gives us a better idea of where in the infection course the person is.
Jaylin’s Thoughts: Microbiology 