The race against COVID-19 has developed into the most widely watched scientific discovery since HIV. However, HIV’s story turned into a long grueling ultra-marathon while COVID is more like the Olympic 1600 meter race with speed hoping for a quick finish. The rapidity of discovery has been both exhilarating and maddening. Each discovery is met with a breath of relief as a piece of the puzzle comes into place. On the other hand, as some discoveries contradict other discoveries, or force some adaptation of what we thought we knew, many become agitated that we can’t get the story straight. This is actually the normal process of science in which we both build on prior discoveries and have to alter our prior misconceptions along the way. The only difference is that we are watching it in 4x fast forward on the movie big screen in real life.
The primary instigating article for this post combines both excitement and potential frustration into one discovery. Researchers from Duke with the National University of Singapore (NUS) Yong Loo Lin School of Medicine, Singapore General Hospital (SGH) and National Centre for Infectious Diseases (NCID) published their findings in the journal Nature recently concerning COVID-19 and T cell immunity. The findings bring excitement as it should improve our current response to COVID-19. The findings could also shake up the COVID 19 response.
Researchers looked at whether patients who recovered from COVID-19 would demonstrate memory T-Cells against the SARS-CoV-2 virus. Our immune system’s T-cells defend against viral infections by identifying and attacking viral infected cells so they are neutralized before replicating millions of virus copies. Their memory T-cell versions remain in our bodies after the infection is conquered so that they can rapidly respond at the first signs of an attempted repeat infectious attack.
In the study, all patients who had recovered from COVID-19 demonstrated the presence of these memory T cells. This is in contrast to other studies showing that not all recovered patients possessed antibodies against SARS-CoV-2 virus which has been considered as a means of determining past infection and/or current immunity. This is where the COVID-19 world gets shaken up. While there is much controversy over the accuracy of COVID-19 antibody testing’s accuracy, we may simply be testing the wrong arm of the immune system. Antibodies are proteins produced in abundance by the immune system’s B cells. They attach to viruses or bacteria or other foreign objects and mark them for attack. If instead, our defense against SARS-CoV-2 lies more within the T-cell arm of the system, then testing for antibodies is less relevant to the COVID-19 response.
Beyond this question of T versus B response that is not yet fully answered, we have another potential paradigm rattling finding from this study. The researchers also looked at those who were not known to have been infected by SARS-CoV-2. Surprisingly, they found that about 50 percent possessed memory T-cells that cross-reacted to the SARS-CoV-2 virus, providing some level of immune defense. They hope to continue research that could help us understand why some fair better against in COVID-19 than others. Possibly, those with the cross-reactivity may respond faster and thus more successfully when infected. They are also following COVID-19 survivors to monitor whether their T-cell immunity endures or fades like the antibody responses appear to do.
If any of you want to jump down the rabbit hole and dig further into T-cell immunity in COVID-19, I have provided a few other resource links. The paper by Vabret et al is a long exposition attempting to combine all prior knowledge of COVID-19 immunology prior to May 6. While we have added to our knowledge in the past few months, the complexity of viral immunity in this paper will leave your head spinning and help you understand why “it just is not that simple”. A Technology News link describes the development of a test kit to assess one’s T-cell immunity to SARS-CoV-2. The article by Melgaco et al discusses the quandary of waning antibodies after infection.
With the breadth and depth of SARS-CoV-2 understanding rapidly expanding, many will have to become “COVID-ologists”. As a functional MD caring for hundreds of patients presenting with a wide variety and complexity of disease processes, I will never be able to qualify as a “COVID-ologist”. However, as a functional MD working to understand and apply foundational understanding of how our immune system serves us, I will strive towards taking the “COVID-ologists” research and applying it to my patients. I look forward to my medical colleagues work in the labs and academic centers shining light into the inner workings of our immune system.
Nina Le Bert, Anthony T. Tan, Kamini Kunasegaran, Christine Y. L. Tham, Morteza Hafezi, Adeline Chia, Melissa Hui Yen Chng, Meiyin Lin, Nicole Tan, Martin Linster, Wan Ni Chia, Mark I-Cheng Chen, Lin-Fa Wang, Eng Eong Ooi, Shirin Kalimuddin, Paul Anantharajal Tambyah, Jenny Guek-Hong Low, Yee-Joo Tan, Antonio Bertoletti. SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls. Nature, 2020; DOI: 10.1038/s41586-020-2550-z
Thanks to Science Daily:
Duke-NUS Medical School. “Scientists uncover SARS-CoV-2-specific T cell immunity in recovered COVID-19 and SARS patients.” ScienceDaily. ScienceDaily, 16 July 2020. <www.sciencedaily.com/releases/2020/07/200716101536.htm>.
Vabret, Nicolas et al. “Immunology of COVID-19: Current State of the Science.” Immunity vol. 52,6 (2020): 910-941. doi:10.1016/j.immuni.2020.05.002
Measuring the T Cell Immune Response to COVID-19. Technology News Networks. https://www.technologynetworks.com/diagnostics/blog/measuring-the-t-cell-immune-response-to-covid-19-337174 Published July 8, 2020. Accessed July 26, 2020.
Melgaço, Juliana Gil et al. “Protective immunity after COVID-19 has been questioned: What can we do without SARS-CoV-2-IgG detection?.” Cellular immunology vol. 353 (2020): 104114. doi:10.1016/j.cellimm.2020.104114
Grifoni, Alba et al. “Targets of T Cell Responses to SARS-CoV-2 Coronavirus in Humans with COVID-19 Disease and Unexposed Individuals.” Cell vol. 181,7 (2020): 1489-1501.e15. doi:10.1016/j.cell.2020.05.015
Bergmann, Cornelia C et al. “Coronavirus immunity: from T cells to B cells.” Advances in experimental medicine and biology vol. 581 (2006): 341-9. doi:10.1007/978-0-387-33012-9_61
Sanctuary Functional Medicine, under the direction of Dr Eric Potter, IFMCP MD, provides functional medicine services to Nashville, Middle Tennessee and beyond. We frequently treat patients from Kentucky, Alabama, Mississippi, Georgia, Ohio, Indiana, and more... offering the hope of healthier more abundant lives to those with chronic illness.