Antibody Response

As Covid-19 cases grow in the United States, many researchers and health care professionals are looking for the right treatment. Luckily, our bodies are also working hard to fight the infection by producing antibodies such as IgM and IgG. The amount of IgM vs. IgG antibodies present in our blood can tell health care workers whether we have been infected and for how long. When only IgM antibody titers are present in your blood, this means that you have only recently been infected with Covid-19 and have not yet created a better antibody response. This can be explained by the fact that IgM antibodies are the first antibodies that are created. Based on Dr. Cramer’s lecture, after about 5 days after your initial exposure to Covid-19 your antibodies will undergo class switching and you will start to create IgG antibodies. These antibodies are better equipped at tackling the virus and you will have a more pronounced immune response. At first, you will have a combination of IgM and IgG antibodies, but over time you will mostly generate IgG antibodies.

If we could determine who has produced a Covid-19 IgG response, we would be able to identify the individuals who have developed a better antibody response against the disease. These individuals would primarily have an IgG antibody titer, suggesting that multiple days have passed since the infection happened and their body has been working to fight the pathogen. This in turn builds their immunity and they are no longer infectious. This could have important clinical implications, since we would be better able to protect those who have not built up immunity. At the moment, scientists believe that individuals who have been infected and recovered from Covid-19 will have up to 2 years of immunity, but it is unclear whether this will last longer. Though this may seem like a rather short time period, any secondary exposure to Covid-19 would most likely result in a less severe infection, due to the memory cells developed by the initial immune response.

Antibody tests are being used around the world to help determine whether an individual has been infected with Covid-19 and what kind of immunity they have started to build. Health care professionals are also considering using the antibodies of individuals who have survived Covid-19 to help treat infected patients. Though this is not a widely used practice, this method has seen some preliminary success. Unfortunately, it is not without risk and the donor’s blood has to undergo a rigorous screening process to make sure that it is safe and free of other diseases. In addition, the donor would have to exhibit an appropriate and strong enough immune response, in order for the treatment to be worthwhile. Researchers are currently working on completing a nationwide study to assess the effectiveness of Covid-19 antibody treatments in the United States, so hopefully we will see more success in the future. I was surprised to learn that this is not a novel practice, rather it has been used to in the past as a way to save soldiers battling viral diseases. This makes me think that this method may be a promising approach, while scientists work to develop a vaccine. Interestingly, the antibody response to Covid-19 is also being used in the development of the Covid-19 vaccine, to make sure that a proper immune response is generated, highlighting how important antibodies are in helping us find a cure. Luckily, we are getting closer each and every day!  

References

Le Page, Michael. “How Does Coronavirus Testing Work and Will We Have a Home Test Soon?” New Scientist, 25 Mar. 2020, https://www.newscientist.com/article/2238477-how-does-coronavirus-testing-work-and-will-we-have-a-home-test-soon/.

Mandavilli, Apoorva. “Can You Become Immune to the Coronavirus?” The New York Times, 25 Mar. 2020, https://www.nytimes.com/2020/03/25/health/coronavirus-immunity-antibodies.html?searchResultPosition=2.

The Associated Press. “Coronavirus Survivor: ‘In My Blood, There May Be Answers.’” The New York Times, 3 Apr. 2020, https://www.nytimes.com/aponline/2020/04/03/us/ap-virus-outbreak-blood-from-the-recovered.html?searchResultPosition=8.