Antibodies, or immunoglobulins, are essential for host defenses. I find this extremely interesting while studying the Coronavirus and learning about different diseases because they directly help neutralize pathogens. There are five major classes of antibody molecules: IgM, IgG, IgA, IgD and IgE. If a person only has IgM antibody titers, this means that it is early in their infection because this is the first class of antibodies during the primary response. If a person has both IgM and IgG antibody titers, it likely means that they are currently fighting the infection because the IgM is still in their system. If someone has primarily an IgG antibody titer, this means that they have probably had the infection at sometime in the past. This is because there is no longer IgM present as well as the fact that IgG circulates in the blood for a long amount of time after the infection has occurred.
The antibody responses for Covid-19 are especially relevant and interesting because of their ability to reveal whether or not a person is/ has been infected by the Coronavirus. Recently, there has been the rapid release of at-home test kits. This relies on the presence of antigens in the persons respiratory tract or detection of antibodies. In the test, these antigens would bind to the antibodies on a plastic casing and indicate whether or not a person has the virus. However, these immunodiagnostic tests are not being recommended to the general public because of their inconsistency.
I also found another article to be extremely fascinating because it was not something that I expected or believe to be a “normal” response to an infection. Researchers in China found that some Coronavirus patients have very low antibody levels for Covid-19. This is concerning because it could mean that the reinfection rate is very high. “The researchers said they were surprised to find that the antibody titer value in about a third of the patients was less than 500.” This will most likely affect the testing of this virus moving forward because the antibody response may not be a great indicator if someone has recovered from the Coronavirus.
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